Integrated snapshot interface for a data storage system

ABSTRACT

A data storage system includes a generic snapshot interface, allowing for integration with a wide variety of snapshot-capable storage devices. The generic interface can be a programming interface (e.g., an application programming interface [API]). Using the snapshot interface, storage device vendors can integrate their particular snapshot technology with the data storage system. For instance, the data storage system can access a shared library of functions (e.g., a dynamically linked library [DLL]) provided by the vendor (or another by appropriate entity) and that complies with the specifications of the common programming interface. And by invoking the appropriate functions in the library, the data storage system implements the snapshot operation on the storage device.

INCORPORATION BY REFERENCE TO RELATED APPLICATIONS

Any and all priority claims identified in the Application Data Sheet, orany correction thereto, are hereby incorporated by reference under 37CFR 1.57.

This application is a continuation of U.S. application Ser. No.15/099,865, filed on Apr. 15, 2016 and entitled INTEGRATED SNAPSHOTINTERFACE FOR A DATA STORAGE SYSTEM, which is a continuation of U.S.application Ser. No. 13/787,643, filed Mar. 6, 2013, and entitledINTEGRATED SNAPSHOT INTERFACE FOR A DATA STORAGE SYSTEM, which claimsthe benefit of priority to U.S. Provisional Patent Application No.61/637,208, filed on Apr. 23, 2012, and entitled “INTEGRATED SNAPSHOTINTERFACE FOR A DATA STORAGE SYSTEM,” each of which is herebyincorporated by reference in its entirety.

BACKGROUND

Businesses worldwide recognize the commercial value of their data andseek reliable, cost-effective ways to protect the information stored ontheir computer networks while minimizing impact on productivity.Protecting information is often part of a routine process that isperformed within an organization.

A company might back up critical computing systems such as databases,file servers, web servers, and so on as part of a daily, weekly, ormonthly maintenance schedule. The company may similarly protectcomputing systems used by each of its employees, such as those used byan accounting department, marketing department, engineering department,and so forth.

Given the rapidly expanding volume of data under management, companiesalso continue to seek innovative techniques for managing data growth, inaddition to protecting data. For instance, companies often implementmigration techniques for moving data to lower cost storage over time anddata reduction techniques for reducing redundant data, pruning lowerpriority data, etc.

Enterprises also increasingly view their stored data as a valuableasset. Along these lines, customers are looking for solutions that notonly protect and manage, but also leverage their data. For instance,solutions providing data analysis capabilities, improved datapresentation and access features, and the like, are in increasingdemand.

SUMMARY

Snapshot technology and management can vary by storage platform, whichcan lead to significant administrative burden. For instance, it can bedesirable to integrate a variety of hardware storage devices (e.g., diskarrays) with data storage and management software. This allows users toexploit the functionality of the data management software. For instance,some data storage and management systems described herein providepolicy-based data protection functions (e.g., backup, archiving,replication, migration, restore, etc.) in an application-consistentmanner. However, integrating a selected storage product (e.g., storagehardware such as a hardware snapshot-capable storage array) with suchdata management software often involves extensive customized scripting,monitoring and maintenance, resulting in added complexity and cost.

Some data storage and management systems provide customized, built-insupport for selected hardware storage products and correspondingsnapshot or other functionality. However, given the large number ofvendors and associated products, incorporating this type of customized,built-in support provides a limited solution.

A data storage system according to certain embodiments includes a hostcomputing device in communication with a first storage device of a firsttype, the first storage device configured to perform snapshotoperations. The system can includes at least one software applicationexecuting on a host computing device and generating production data. Thesystem includes a snapshot management module executing on one or moreprocessors and configured to: receive a request to perform a snapshotoperation involving a stored version of at least a portion of theproduction data that resides on the first storage device; process therequest to identify one or more functions for performing the requestedsnapshot operation and that are defined at least in part by aprogramming interface specification; and invoke instances of the one ormore identified functions that are in compliance with the programminginterface specification and are implemented specifically for storagedevices of the first type. A snapshot engine residing on the firststorage device is responsive to the invoking of the instances of the oneor more identified functions to perform the requested snapshotoperation.

According to certain aspects, a method is provided for performing one ormore snapshot operations on production data generated in a data storagesystem. The method can include receiving a request to perform a snapshotoperation involving a stored version of at least a portion of productiondata that resides on a first storage device of a first type, theproduction data generated by at least one software application executingon a host computing device that is in communication with the firststorage device, the first storage device configured to perform snapshotoperations. The method can also include processing the request using oneor more computer processors to identify one or more functions forperforming the requested snapshot operation and that are defined atleast in part by a programming interface specification. The methodfurther includes invoking, using one or more computer processors,instances of the one or more identified functions that are in compliancewith the programming interface specification and are implementedspecifically for storage devices of the first type. A snapshot engineresiding on the first storage device is responsive to the invoking ofthe instances of the one or more identified functions to perform therequested snapshot operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram illustrating an exemplary informationmanagement system.

FIG. 1B is a detailed view of a primary storage device, a secondarystorage device, and some examples of primary data and secondary copydata.

FIG. 1C is a block diagram of an exemplary information management systemincluding a storage manager, one or more data agents, and one or moremedia agents.

FIG. 1D is a block diagram illustrating a scalable informationmanagement system.

FIG. 1E illustrates certain secondary copy operations according to anexemplary storage policy.

FIGS. 2A-2B illustrate example data storage systems implementing acommon snapshot interface in accordance with certain embodiments.

FIG. 3A illustrates an example data storage system implementing a commonsnapshot interface and in which data is copied to one or moredestination systems.

FIG. 3B-3C illustrate example operational flows for performing storageoperations using the data storage system of FIG. 3A.

FIG. 4 is a flowchart illustrating an example method for performingsnapshot operations using a common snapshot interface, in accordancewith embodiments described herein.

DETAILED DESCRIPTION

In response to the foregoing challenges, certain embodiments describedherein include data storage systems capable of supporting a wide varietyof hardware storage devices, including products provided by multiplevendors. And these data storage systems support using an integrated,single-platform architecture. In some cases, the data storage systemprovides a generic snapshot interface, allowing for integration with awide variety of snapshot-capable storage devices.

The generic interface can be a programming interface (e.g., anapplication programming interface [API]). Using the snapshot interface,storage device vendors can integrate their particular snapshottechnology with the data storage system. For instance, the data storagesystem can access a shared library of functions (e.g., a dynamicallylinked library [DLL]) provided by the vendor (or another by appropriateentity) that complies with the specifications of the common programminginterface. And by invoking the appropriate functions in the library, thedata storage system performs the snapshot operation on the storagedevice.

In this manner, users can exploit the advantages of the data storagesystem (e.g., policy-based, application-consistent data management andprotection) with generally any type of snapshot-capable storage device.

Moreover, because vendors are generally experts regarding the underlyingimplementation of their respective snapshot-capable products, they arewell-suited to develop the library. Thus, the task of implementing thelibrary instances for the particular storage devices can be distributedto a large number of expert parties, such as the vendors. In these andother manners, the generic interface allows the data storage system tosupport a large number of different snapshot products in an efficientand scalable manner.

In some embodiments, the data storage system includes built-infunctionality for interacting with a first group of one or more types ofsnapshot devices, and the generic interface provides compatibility witha second group of one or more types of snapshot devices.

Systems and methods are described herein for implementing an integratedsnapshot interface in a data storage system. Examples of such systemsand methods are discussed in further detail herein, e.g., with respectto FIGS. 2-4. An integrated snapshot interface may additionally beimplemented by information management systems such as those that willnow be described with respect to FIGS. 1A-1E. And, as will be described,the componentry for implementing the integrated snapshot interfacedescribed herein can be incorporated into and implemented by suchsystems.

Information Management System Overview

With the increasing importance of protecting and leveraging data,organizations simply cannot afford to take the risk of losing criticaldata. Moreover, runaway data growth and other modern realities makeprotecting and managing data an increasingly difficult task. There istherefore a need for efficient, powerful, and user-friendly solutionsfor protecting and managing data.

Depending on the size of the organization, there are typically many dataproduction sources which are under the purview of tens, hundreds, oreven thousands of employees or other individuals. In the past,individual employees were sometimes responsible for managing andprotecting their data. A patchwork of hardware and software pointsolutions have been applied in other cases. These solutions were oftenprovided by different vendors and had limited or no interoperability.

Certain embodiments described herein provide systems and methods capableof addressing these and other shortcomings of prior approaches byimplementing unified, organization-wide information management. FIG. 1Ashows one such information management system 100, which generallyincludes combinations of hardware and software configured to protect andmanage data and metadata generated and used by the various computingdevices in the information management system 100.

The organization which employs the information management system 100 maybe a corporation or other business entity, non-profit organization,educational institution, household, governmental agency, or the like.

Generally, the systems and associated components described herein may becompatible with and/or provide some or all of the functionality of thesystems and corresponding components described in one or more of thefollowing U.S. patents and patent application publications assigned toCommVault Systems, Inc., each of which is hereby incorporated in itsentirety by reference herein:

U.S. Pat. Pub. No. 2010-0332456, entitled “DATA OBJECT STORE AND SERVERFOR A CLOUD STORAGE ENVIRONMENT, INCLUDING DATA DEDUPLICATION AND DATAMANAGEMENT ACROSS MULTIPLE CLOUD STORAGE SITES”;

U.S. Pat. No. 7,035,880, entitled “MODULAR BACKUP AND RETRIEVAL SYSTEMUSED IN CONJUNCTION WITH A STORAGE AREA NETWORK”;

U.S. Pat. No. 7,343,453, entitled “HIERARCHICAL SYSTEMS AND METHODS FORPROVIDING A UNIFIED VIEW OF STORAGE INFORMATION”;

U.S. Pat. No. 7,395,282, entitled “HIERARCHICAL BACKUP AND RETRIEVALSYSTEM”;

U.S. Pat. No. 7,246,207, entitled “SYSTEM AND METHOD FOR DYNAMICALLYPERFORMING STORAGE OPERATIONS IN A COMPUTER NETWORK”;

U.S. Pat. No. 7,747,579, entitled “METABASE FOR FACILITATING DATACLASSIFICATION”;

U.S. Pat. No. 8,229,954, entitled “MANAGING COPIES OF DATA”;

U.S. Pat. No. 7,617,262, entitled “SYSTEM AND METHODS FOR MONITORINGAPPLICATION DATA IN A DATA REPLICATION SYSTEM”;

U.S. Pat. No. 7,529,782, entitled “SYSTEM AND METHODS FOR PERFORMING ASNAPSHOT AND FOR RESTORING DATA”;

U.S. Pat. No. 8,230,195, entitled “SYSTEM AND METHOD FOR PERFORMINGAUXILIARY STORAGE OPERATIONS”;

U.S. Pat. No. 8,364,652, entitled “CONTENT-ALIGNED, BLOCK-BASEDDEDUPLICATION”;

U.S. Pat. Pub. No. 2006/0224846, entitled “SYSTEM AND METHOD TO SUPPORTSINGLE INSTANCE STORAGE OPERATIONS”;

U.S. Pat. Pub. No. 2009/0329534, entitled “APPLICATION-AWARE AND REMOTESINGLE INSTANCE DATA MANAGEMENT”;

U.S. Pat. Pub. No. 2012/0150826, entitled “DISTRIBUTED DEDUPLICATEDSTORAGE SYSTEM”;

U.S. Pat. Pub. No. 2012/0150818, entitled “CLIENT-SIDE REPOSITORY IN ANETWORKED DEDUPLICATED STORAGE SYSTEM”;

U.S. Pat. No. 8,170,995, entitled “METHOD AND SYSTEM FOR OFFLINEINDEXING OF CONTENT AND CLASSIFYING STORED DATA”; and

U.S. Pat. No. 8,156,086, entitled “SYSTEMS AND METHODS FOR STORED DATAVERIFICATION”.

The illustrated information management system 100 includes one or moreclient computing device 102 having at least one application 110executing thereon, and one or more primary storage devices 104 storingprimary data 112. The client computing device(s) 102 and the primarystorage devices 104 may generally be referred to in some cases as aprimary storage subsystem 117.

Depending on the context, the term “information management system” canrefer to generally all of the illustrated hardware and softwarecomponents. Or, in other instances, the term may refer to only a subsetof the illustrated components.

For instance, in some cases information management system 100 generallyrefers to a combination of specialized components used to protect, move,manage, manipulate and/or process data and metadata generated by theclient computing devices 102. However, the term may generally not referto the underlying components that generate and/or store the primary data112, such as the client computing devices 102 themselves, theapplications 110 and operating system residing on the client computingdevices 102, and the primary storage devices 104.

As an example, “information management system” may sometimes refer onlyto one or more of the following components and corresponding datastructures: storage managers, data agents, and media agents. Thesecomponents will be described in further detail below.

Client Computing Devices

There are typically a variety of sources in an organization that producedata to be protected and managed. As just one illustrative example, in acorporate environment such data sources can be employee workstations andcompany servers such as a mail server, a web server, or the like. In theinformation management system 100, the data generation sources includethe one or more client computing devices 102.

The client computing devices 102 may include, without limitation, one ormore: workstations, personal computers, desktop computers, or othertypes of generally fixed computing systems such as mainframe computersand minicomputers.

The client computing devices 102 can also include mobile or portablecomputing devices, such as one or more laptops, tablet computers,personal data assistants, mobile phones (such as smartphones), and othermobile or portable computing devices such as embedded computers, set topboxes, vehicle-mounted devices, wearable computers, etc.

In some cases, each client computing device 102 is associated with oneor more users and/or corresponding user accounts, of employees or otherindividuals.

The term “client computing device” is used herein because theinformation management system 100 generally “serves” the data managementand protection needs for the data generated by the client computingdevices 102. However, the use of this term does not imply that theclient computing devices 102 cannot be “servers” in other respects. Forinstance, a particular client computing device 102 may act as a serverwith respect to other devices, such as other client computing devices102. As just a few examples, the client computing devices 102 caninclude mail servers, file servers, database servers, and web servers.

The client computing devices 102 may additionally include virtualizedand/or cloud computing resources. For instance, one or more virtualmachines may be provided to the organization by a third-party cloudservice vendor. Or, in some embodiments, the client computing devices102 include one or more virtual machine(s) running on a virtual machinehost computing device operated by the organization. As one example, theorganization may use one virtual machine as a database server andanother virtual machine as a mail server. A virtual machine manager(VMM) (e.g., a Hypervisor) may manage the virtual machines, and resideand execute on the virtual machine host computing device.

Each client computing device 102 may have one or more applications 110(e.g., software applications) executing thereon which generate andmanipulate the data that is to be protected from loss.

The applications 110 generally facilitate the operations of anorganization (or multiple affiliated organizations), and can include,without limitation, mail server applications (e.g., Microsoft ExchangeServer), file server applications, mail client applications (e.g.,Microsoft Exchange Client), database applications (e.g., SQL, Oracle,SAP, Lotus Notes Database), word processing applications (e.g.,Microsoft Word), spreadsheet applications, financial applications,presentation applications, browser applications, mobile applications,entertainment applications, and so on.

The applications 110 can include at least one operating system (e.g.,Microsoft Windows, Mac OS X, iOS, IBM z/OS, Linux, other Unix-basedoperating systems, etc.), which may support one or more file systems andhost the other applications 110.

As shown, the client computing devices 102 and other components in theinformation management system 100 can be connected to one another viaone or more communication pathways 114. The communication pathways 114can include one or more networks or other connection types including asany of following, without limitation: the Internet, a wide area network(WAN), a local area network (LAN), a Storage Area Network (SAN), a FibreChannel connection, a Small Computer System Interface (SCSI) connection,a virtual private network (VPN), a token ring or TCP/IP based network,an intranet network, a point-to-point link, a cellular network, awireless data transmission system, a two-way cable system, aninteractive kiosk network, a satellite network, a broadband network, abaseband network, other appropriate wired, wireless, or partiallywired/wireless computer or telecommunications networks, combinations ofthe same or the like. The communication pathways 114 in some cases mayalso include application programming interfaces (APIs) including, e.g.,cloud service provider APIs, virtual machine management APIs, and hostedservice provider APIs.

Primary Data and Exemplary Primary Storage Devices

Primary data 112 according to some embodiments is production data orother “live” data generated by the operating system and otherapplications 110 residing on a client computing device 102. The primarydata 112 is stored on the primary storage device(s) 104 and is organizedvia a file system supported by the client computing device 102. Forinstance, the client computing device(s) 102 and correspondingapplications 110 may create, access, modify, write, delete, andotherwise use primary data 112.

Primary data 112 is generally in the native format of the sourceapplication 110. According to certain aspects, primary data 112 is aninitial or first (e.g., created before any other copies or before atleast one other copy) stored copy of data generated by the sourceapplication 110. Primary data 112 in some cases is created substantiallydirectly from data generated by the corresponding source applications110.

The primary data 112 may sometimes be referred to as a “primary copy” inthe sense that it is a discrete set of data. However, the use of thisterm does not necessarily imply that the “primary copy” is a copy in thesense that it was copied or otherwise derived from another storedversion.

The primary storage devices 104 storing the primary data 112 may berelatively fast and/or expensive (e.g., a disk drive, a hard-disk array,solid state memory, etc.). In addition, primary data 112 may be intendedfor relatively short term retention (e.g., several hours, days, orweeks).

According to some embodiments, the client computing device 102 canaccess primary data 112 from the primary storage device 104 by makingconventional file system calls via the operating system. Primary data112 representing files may include structured data (e.g., databasefiles), unstructured data (e.g., documents), and/or semi-structureddata. Some specific examples are described below with respect to FIG.1B.

It can be useful in performing certain tasks to break the primary data112 up into units of different granularities. In general, primary data112 can include files, directories, file system volumes, data blocks,extents, or any other types or granularities of data objects. As usedherein, a “data object” can refer to both (1) any file that is currentlyaddressable by a file system or that was previously addressable by thefile system (e.g., an archive file) and (2) a subset of such a file.

As will be described in further detail, it can also be useful inperforming certain functions of the information management system 100 toaccess and modify metadata within the primary data 112. Metadatagenerally includes information about data objects or characteristicsassociated with the data objects.

Metadata can include, without limitation, one or more of the following:the data owner (e.g., the client or user that generates the data), thelast modified time (e.g., the time of the most recent modification ofthe data object), a data object name (e.g., a file name), a data objectsize (e.g., a number of bytes of data), information about the content(e.g., an indication as to the existence of a particular search term),to/from information for email (e.g., an email sender, recipient, etc.),creation date, file type (e.g., format or application type), lastaccessed time, application type (e.g., type of application thatgenerated the data object), location/network (e.g., a current, past orfuture location of the data object and network pathways to/from the dataobject), frequency of change (e.g., a period in which the data object ismodified), business unit (e.g., a group or department that generates,manages or is otherwise associated with the data object), and aginginformation (e.g., a schedule, such as a time period, in which the dataobject is migrated to secondary or long term storage), boot sectors,partition layouts, file location within a file folder directorystructure, user permissions, owners, groups, access control lists[ACLs]), system metadata (e.g., registry information), combinations ofthe same or the like.

In addition to metadata generated by or related to file systems andoperating systems, some of the applications 110 maintain indices ofmetadata for data objects, e.g., metadata associated with individualemail messages. Thus, each data object may be associated withcorresponding metadata. The use of metadata to perform classificationand other functions is described in greater detail below.

Each of the client computing devices 102 are associated with and/or incommunication with one or more of the primary storage devices 104storing corresponding primary data 112. A client computing device 102may be considered to be “associated with” or “in communication with” aprimary storage device 104 if it is capable of one or more of: storingdata to the primary storage device 104, retrieving data from the primarystorage device 104, and modifying data retrieved from a primary storagedevice 104.

The primary storage devices 104 can include, without limitation, diskdrives, hard-disk arrays, semiconductor memory (e.g., solid statedrives), and network attached storage (NAS) devices. In some cases, theprimary storage devices 104 form part of a distributed file system. Theprimary storage devices 104 may have relatively fast I/O times and/orare relatively expensive in comparison to the secondary storage devices108. For example, the information management system 100 may generallyregularly access data and metadata stored on primary storage devices104, whereas data and metadata stored on the secondary storage devices108 is accessed relatively less frequently.

In some cases, each primary storage device 104 is dedicated to anassociated client computing devices 102. For instance, a primary storagedevice 104 in one embodiment is a local disk drive of a correspondingclient computing device 102. In other cases, one or more primary storagedevices 104 can be shared by multiple client computing devices 102. Asone example, a primary storage device 104 can be a disk array shared bya group of client computing devices 102, such as one of the followingtypes of disk arrays: EMC Clariion, EMC Symmetrix, EMC Celerra, DellEqualLogic, IBM XIV, NetApp FAS, HP EVA, and HP SPAR.

The information management system 100 may also include hosted services(not shown), which may be hosted in some cases by an entity other thanthe organization that employs the other components of the informationmanagement system 100. For instance, the hosted services may be providedby various online service providers to the organization. Such serviceproviders can provide services including social networking services,hosted email services, or hosted productivity applications or otherhosted applications).

Hosted services may include software-as-a-service (SaaS),platform-as-a-service (PaaS), application service providers (ASPs),cloud services, or other mechanisms for delivering functionality via anetwork. As it provides services to users, each hosted service maygenerate additional data and metadata under management of theinformation management system 100, e.g., as primary data 112. In somecases, the hosted services may be accessed using one of the applications110. As an example, a hosted mail service may be accessed via browserrunning on a client computing device 102.

Secondary Copies and Exemplary Secondary Storage Devices

The primary data 112 stored on the primary storage devices 104 may becompromised in some cases, such as when an employee deliberately oraccidentally deletes or overwrites primary data 112 during their normalcourse of work. Or the primary storage devices 104 can be damaged orotherwise corrupted.

For recovery and/or regulatory compliance purposes, it is thereforeuseful to generate copies of the primary data 112. Accordingly, theinformation management system 100 includes one or more secondary storagecomputing devices 106 and one or more secondary storage devices 108configured to create and store one or more secondary copies 116 of theprimary data 112 and associated metadata. The secondary storagecomputing devices 106 and the secondary storage devices 108 may bereferred to in some cases as a secondary storage subsystem 118.

Creation of secondary copies 116 can help meet information managementgoals, such as: restoring data and/or metadata if an original version(e.g., of primary data 112) is lost (e.g., by deletion, corruption, ordisaster); allowing point-in-time recovery; complying with regulatorydata retention and electronic discovery (e-discovery) requirements;reducing utilized storage capacity; facilitating organization and searchof data; improving user access to data files across multiple computingdevices and/or hosted services; and implementing data retentionpolicies.

Types of secondary copy operations can include, without limitation,backup operations, archive operations, snapshot operations, replicationoperations (e.g., continuous data replication [CDR]), data retentionpolicies such as information lifecycle management and hierarchicalstorage management operations, and the like. These specific typesoperations are discussed in greater detail below.

Regardless of the type of secondary copy operation, the client computingdevices 102 access or receive primary data 112 and communicate the data,e.g., over the communication pathways 114, for storage in the secondarystorage device(s) 108.

A secondary copy 116 can comprise a separate stored copy of applicationdata that is derived from one or more earlier created, stored copies(e.g., derived from primary data 112 or another secondary copy 116).Secondary copies 116 can include point-in-time data, and may be intendedfor relatively long-term retention (e.g., weeks, months or years),before some or all of the data is moved to other storage or isdiscarded.

In some cases, a secondary copy 116 is a copy of application datacreated and stored subsequent to at least one other stored instance(e.g., subsequent to corresponding primary data 112 or to anothersecondary copy 116), in a different storage device than at least oneprevious stored copy, and/or remotely from at least one previous storedcopy. Secondary copies 116 may be stored in relatively slow and/or lowcost storage (e.g., magnetic tape). A secondary copy 116 may be storedin a backup or archive format, or in some other format different thanthe native source application format or other primary data format.

In some cases, secondary copies 116 are indexed so users can browse andrestore at another point in time. After creation of a secondary copy 116representative of certain primary data 112, a pointer or other locationindicia (e.g., a stub) may be placed in primary data 112, or beotherwise associated with primary data 112 to indicate the currentlocation on the secondary storage device(s) 108.

Since an instance a data object or metadata in primary data 112 maychange over time as it is modified by an application 110 (or hostedservice or the operating system), the information management system 100may create and manage multiple secondary copies 116 of a particular dataobject or metadata, each representing the state of the data object inprimary data 112 at a particular point in time. Moreover, since aninstance of a data object in primary data 112 may eventually be deletedfrom the primary storage device 104 and the file system, the informationmanagement system 100 may continue to manage point-in-timerepresentations of that data object, even though the instance in primarydata 112 no longer exists.

For virtualized computing devices the operating system and otherapplications 110 of the client computing device(s) 102 may executewithin or under the management of virtualization software (e.g., a VMM),and the primary storage device(s) 104 may comprise a virtual diskcreated on a physical storage device. The information management system100 may create secondary copies 116 of the files or other data objectsin a virtual disk file and/or secondary copies 116 of the entire virtualdisk file itself (e.g., of an entire .vmdk file).

Secondary copies 116 may be distinguished from corresponding primarydata 112 in a variety of ways, some of which will now be described.First, as discussed, secondary copies 116 can be stored in a differentformat (e.g., backup, archive, or other non-native format) than primarydata 112. For this or other reasons, secondary copies 116 may not bedirectly useable by the applications 110 of the client computing device102, e.g., via standard system calls or otherwise without modification,processing, or other intervention by the information management system100.

Secondary copies 116 are also often stored on a secondary storage device108 that is inaccessible to the applications 110 running on the clientcomputing devices 102 (and/or hosted services). Some secondary copies116 may be “offline copies,” in that they are not readily available(e.g. not mounted to tape or disk). Offline copies can include copies ofdata that the information management system 100 can access without humanintervention (e.g. tapes within an automated tape library, but not yetmounted in a drive), and copies that the information management system100 can access only with at least some human intervention (e.g. tapeslocated at an offsite storage site).

The secondary storage devices 108 can include any suitable type ofstorage device such as, without limitation, one or more tape libraries,disk drives or other magnetic, non-tape storage devices, optical mediastorage devices, solid state storage devices, NAS devices, combinationsof the same, and the like. In some cases, the secondary storage devices108 are provided in a cloud (e.g. a private cloud or one operated by athird-party vendor).

The secondary storage device(s) 108 in some cases comprises a disk arrayor a portion thereof. In some cases, a single storage device (e.g., adisk array) is used for storing both primary data 112 and at least somesecondary copies 116. In one example, a disk array capable of performinghardware snapshots stores primary data 112 and creates and storeshardware snapshots of the primary data 112 as secondary copies 116.

The Use of Intermediary Devices for Creating Secondary Copies

Creating secondary copies can be a challenging task. For instance, therecan be hundreds or thousands of client computing devices 102 continuallygenerating large volumes of primary data 112 to be protected. Also,there can be significant overhead involved in the creation of secondarycopies 116. Moreover, secondary storage devices 108 may be specialpurpose components, and interacting with them can require specializedintelligence.

In some cases, the client computing devices 102 interact directly withthe secondary storage device 108 to create the secondary copies 116.However, in view of the factors described above, this approach cannegatively impact the ability of the client computing devices 102 toserve the applications 110 and produce primary data 112. Further, theclient computing devices 102 may not be optimized for interaction withthe secondary storage devices 108.

Thus, in some embodiments, the information management system 100includes one or more software and/or hardware components which generallyact as intermediaries between the client computing devices 102 and thesecondary storage devices 108. In addition to off-loading certainresponsibilities from the client computing devices 102, theseintermediary components can provide other benefits. For instance, asdiscussed further below with respect to FIG. 1D, distributing some ofthe work involved in creating secondary copies 116 can enhancescalability.

The intermediary components can include one or more secondary storagecomputing devices 106 as shown in FIG. 1A and/or one or more mediaagents, which can be software modules residing on correspondingsecondary storage computing devices 106 (or other appropriate devices).Media agents are discussed below (e.g., with respect to FIGS. 1C-1E).

The secondary storage computing device(s) 106 can comprise anyappropriate type of computing device and can include, withoutlimitation, any of the types of fixed and portable computing devicesdescribed above with respect to the client computing devices 102. Insome cases, the secondary storage computing device(s) 106 includespecialized hardware and/or software componentry for interacting withthe secondary storage devices 108.

To create a secondary copy 116, the client computing device 102communicates the primary data 112 to be copied (or a processed versionthereof) to the designated secondary storage computing device 106, viathe communication pathway 114. The secondary storage computing device106 in turn conveys the received data (or a processed version thereof)to the secondary storage device 108. In some such configurations, thecommunication pathway 114 between the client computing device 102 andthe secondary storage computing device 106 comprises a portion of a LAN,WAN or SAN. In other cases, at least some client computing devices 102communicate directly with the secondary storage devices 108 (e.g., viaFibre Channel or SCSI connections).

Exemplary Primary Data and an Exemplary Secondary Copy

FIG. 1B is a detailed view showing some specific examples of primarydata stored on the primary storage device(s) 104 and secondary copy datastored on the secondary storage device(s) 108, with other components inthe system removed for the purposes of illustration. Stored on theprimary storage device(s) 104 are primary data objects including wordprocessing documents 119A-B, spreadsheets 120, presentation documents122, video files 124, image files 126, email mailboxes 128 (andcorresponding email messages 129A-C), html/xml or other types of markuplanguage files 130, databases 132 and corresponding tables 133A-133C).

Some or all primary data objects are associated with a primary copy ofobject metadata (e.g., “Meta1-11”), which may be file system metadataand/or application specific metadata. Stored on the secondary storagedevice(s) 108 are secondary copy objects 134A-C which may include copiesof or otherwise represent corresponding primary data objects andmetadata.

As shown, the secondary copy objects 134A-C can individually representmore than one primary data object. For example, secondary copy dataobject 134A represents three separate primary data objects 133C, 122 and129C (represented as 133C′, 122′ and 129C′, respectively). Moreover, asindicated by the prime mark (′), a secondary copy object may store arepresentation of a primary data object or metadata differently than theoriginal format, e.g., in a compressed, encrypted, deduplicated, orother modified format.

Exemplary Information Management System Architecture

The information management system 100 can incorporate a variety ofdifferent hardware and software components, which can in turn beorganized with respect to one another in many different configurations,depending on the embodiment. There are critical design choices involvedin specifying the functional responsibilities of the components and therole of each component in the information management system 100. Forinstance, as will be discussed, such design choices can impactperformance as well as the adaptability of the information managementsystem 100 to data growth or other changing circumstances.

FIG. 10 shows an information management system 100 designed according tothese considerations and which includes: a central storage orinformation manager 140 configured to perform certain control functions,one or more data agents 142 executing on the client computing device(s)102 configured to process primary data 112, and one or more media agents144 executing on the one or more secondary storage computing devices 106for performing tasks involving the secondary storage devices 108.

Storage Manager

As noted, the number of components in the information management system100 and the amount of data under management can be quite large. Managingthe components and data is therefore a significant task, and a task thatcan grow in an often unpredictable fashion as the quantity of componentsand data scale to meet the needs of the organization.

For these and other reasons, according to certain embodiments,responsibility for controlling the information management system 100, orat least a significant portion of that responsibility, is allocated tothe storage manager 140.

By distributing control functionality in this manner, the storagemanager 140 can be adapted independently according to changingcircumstances. Moreover, a host computing device can be selected to bestsuit the functions of the storage manager 140. These and otheradvantages are described in further detail below with respect to FIG.1D.

The storage manager 140 may be a software module or other application.The storage manager generally initiates, coordinates and/or controlsstorage and other information management operations performed by theinformation management system 100, e.g., to protect and control theprimary data 112 and secondary copies 116 of data and metadata.

As shown by the dashed, arrowed lines, the storage manager 140 maycommunicate with and/or control some or all elements of the informationmanagement system 100, such as the data agents 142 and media agents 144.Thus, in certain embodiments, control information originates from thestorage manager 140, whereas payload data and metadata is generallycommunicated between the data agents 142 and the media agents 144 (orotherwise between the client computing device(s) 102 and the secondarystorage computing device(s) 106), e.g., at the direction of the storagemanager 140. In other embodiments, some information managementoperations are controlled by other components in the informationmanagement system 100 (e.g., the media agent(s) 144 or data agent(s)142), instead of or in combination with the storage manager 140.

According to certain embodiments, the storage manager provides one ormore of the following functions:

-   -   initiating execution of secondary copy operations;    -   managing secondary storage devices 108 and inventory/capacity of        the same;    -   allocating secondary storage devices 108 for secondary storage        operations;    -   monitoring completion of and providing status reporting related        to secondary storage operations;    -   tracking age information relating to secondary copies 116,        secondary storage devices 108, and comparing the age information        against retention guidelines;    -   tracking movement of data within the information management        system 100;    -   tracking logical associations between components in the        information management system 100;    -   protecting metadata associated with the information management        system 100; and    -   implementing operations management functionality.

The storage manager 140 may maintain a database 146 ofmanagement-related data and information management policies 148. Thedatabase 146 may include a management index 150 or other data structurethat stores logical associations between components of the system, userpreferences and/or profiles (e.g., preferences regarding encryption,compression, or deduplication of primary or secondary copy data,preferences regarding the scheduling, type, or other aspects of primaryor secondary copy or other operations, mappings of particularinformation management users or user accounts to certain computingdevices or other components, etc.), management tasks, mediacontainerization, or other useful data. For example, the storage manager140 may use the index 150 to track logical associations between mediaagents 144 and secondary storage devices 108 and/or movement of datafrom primary storage devices 104 to secondary storage devices 108.

Administrators and other employees may be able to manually configure andinitiate certain information management operations on an individualbasis. But while this may be acceptable for some recovery operations orother relatively less frequent tasks, it is often not workable forimplementing on-going organization-wide data protection and management.

Thus, the information management system 100 may utilize informationmanagement policies 148 for specifying and executing informationmanagement operations (e.g., on an automated basis). Generally, aninformation management policy 148 can include a data structure or otherinformation source that specifies a set of parameters (e.g., criteriaand rules) associated with storage or other information managementoperations.

The storage manager database 146 may maintain the information managementpolicies 148 and associated data, although the information managementpolicies 148 can be stored in any appropriate location. For instance, astorage policy may be stored as metadata in a media agent database 152or in a secondary storage device 108 (e.g., as an archive copy) for usein restore operations or other information management operations,depending on the embodiment. Information management policies 148 aredescribed further below.

According to certain embodiments, the storage manager database 146comprises a relational database (e.g., an SQL database) for trackingmetadata, such as metadata associated with secondary copy operations(e.g., what client computing devices 102 and corresponding data wereprotected). This and other metadata may additionally be stored in otherlocations, such as at the secondary storage computing devices 106 or onthe secondary storage devices 108, allowing data recovery without theuse of the storage manager 140.

As shown, the storage manager 140 may include a jobs agent 156, a userinterface 158, and a management agent 154, all of which may beimplemented as interconnected software modules or application programs.

The jobs agent 156 in some embodiments initiates, controls, and/ormonitors the status of some or all storage or other informationmanagement operations previously performed, currently being performed,or scheduled to be performed by the information management system 100.For instance, the jobs agent 156 may access information managementpolicies 148 to determine when and how to initiate and control secondarycopy and other information management operations, as will be discussedfurther.

The user interface 158 may include information processing and displaysoftware, such as a graphical user interface (“GUI”), an applicationprogram interface (“API”), or other interactive interface through whichusers and system processes can retrieve information about the status ofinformation management operations (e.g., storage operations) or issueinstructions to the information management system 100 and itsconstituent components.

The storage manager 140 may also track information that permits it toselect, designate, or otherwise identify content indices, deduplicationdatabases, or similar databases or resources or data sets within itsinformation management cell (or another cell) to be searched in responseto certain queries. Such queries may be entered by the user viainteraction with the user interface 158.

Via the user interface 158, users may optionally issue instructions tothe components in the information management system 100 regardingperformance of storage and recovery operations. For example, a user maymodify a schedule concerning the number of pending secondary copyoperations. As another example, a user may employ the GUI to view thestatus of pending storage operations or to monitor the status of certaincomponents in the information management system 100 (e.g., the amount ofcapacity left in a storage device).

In general, the management agent 154 allows multiple informationmanagement systems 100 to communicate with one another. For example, theinformation management system 100 in some cases may be one informationmanagement subsystem or “cell” of a network of multiple cells adjacentto one another or otherwise logically related in a WAN or LAN. With thisarrangement, the cells may be connected to one another throughrespective management agents 154.

For instance, the management agent 154 can provide the storage manager140 with the ability to communicate with other components within theinformation management system 100 (and/or other cells within a largerinformation management system) via network protocols and applicationprogramming interfaces (“APIs”) including, e.g., HTTP, HTTPS, FTP, REST,virtualization software APIs, cloud service provider APIs, and hostedservice provider APIs. Inter-cell communication and hierarchy isdescribed in greater detail in U.S. Pat. No. 7,035,880, which isincorporated by reference herein.

Data Agents

As discussed, a variety of different types of applications 110 canreside on a given client computing device 102, including operatingsystems, database applications, e-mail applications, and virtualmachines, just to name a few. And, as part of the as part of the processof creating and restoring secondary copies 116, the client computingdevices 102 may be tasked with processing and preparing the primary data112 from these various different applications 110. Moreover, the natureof the processing/preparation can differ across clients and applicationtypes, e.g., due to inherent structural and formatting differencesbetween applications 110.

The one or more data agent(s) 142 are therefore advantageouslyconfigured in some embodiments to assist in the performance ofinformation management operations based on the type of data that isbeing protected, at a client-specific and/or application-specific level.

The data agent 142 may be a software module or component that isgenerally responsible for managing, initiating, or otherwise assistingin the performance of information management operations. For instance,the data agent 142 may take part in performing data storage operationssuch as the copying, archiving, migrating, replicating of primary data112 stored in the primary storage device(s) 104. The data agent 142 mayreceive control information from the storage manager 140, such ascommands to transfer copies of data objects, metadata, and other payloaddata to the media agents 144.

In some embodiments, a data agent 142 may be distributed between theclient computing device 102 and storage manager 140 (and any otherintermediate components) or may be deployed from a remote location orits functions approximated by a remote process that performs some or allof the functions of data agent 142. In addition, a data agent 142 mayperform some functions provided by a media agent 144, e.g., encryptionand deduplication.

As indicated, each data agent 142 may be specialized for a particularapplication 110, and the system can employ multiple data agents 142,each of which may backup, migrate, and recover data associated with adifferent application 110. For instance, different individual dataagents 142 may be designed to handle Microsoft Exchange data, LotusNotes data, Microsoft Windows file system data, Microsoft ActiveDirectory Objects data, SQL Server data, SharePoint data, Oracledatabase data, SAP database data, virtual machines and/or associateddata, and other types of data.

A file system data agent, for example, may handle data files and/orother file system information. If a client computing device 102 has twoor more types of data, one data agent 142 may be used for each data typeto copy, archive, migrate, and restore the client computing device 102data. For example, to backup, migrate, and restore all of the data on aMicrosoft Exchange server, the client computing device 102 may use oneMicrosoft Exchange Mailbox data agent 142 to backup the Exchangemailboxes, one Microsoft Exchange Database data agent 142 to backup theExchange databases, one Microsoft Exchange Public Folder data agent 142to backup the Exchange Public Folders, and one Microsoft Windows FileSystem data agent 142 to backup the file system of the client computingdevice 102. In such embodiments, these data agents 142 may be treated asfour separate data agents 142 even though they reside on the same clientcomputing device 102.

Other embodiments may employ one or more generic data agents 142 thatcan handle and process data from two or more different applications 110,or that can handle and process multiple data types, instead of or inaddition to using specialized data agents 142. For example, one genericdata agent 142 may be used to back up, migrate and restore MicrosoftExchange Mailbox data and Microsoft Exchange Database data while anothergeneric data agent may handle Microsoft Exchange Public Folder data andMicrosoft Windows File System data.

Each data agent 142 may be configured to access data and/or metadatastored in the primary storage device(s) 104 associated with the dataagent 142 and process the data as appropriate. For example, during asecondary copy operation, the data agent 142 may arrange or assemble thedata and metadata into one or more files having a certain format (e.g.,a particular backup or archive format) before transferring the file(s)to a media agent 144 or other component. The file(s) may include a listof files or other metadata. Each data agent 142 can also assist inrestoring data or metadata to primary storage devices 104 from asecondary copy 116. For instance, the data agent 142 may operate inconjunction with the storage manager 140 and one or more of the mediaagents 144 to restore data from secondary storage device(s) 108.

Media Agents

As indicated above with respect to FIG. 1A, off-loading certainresponsibilities from the client computing devices 102 to intermediarycomponents such as the media agent(s) 144 can provide a number ofbenefits including improved client computing device 102 operation,faster secondary copy operation performance, and enhanced scalability.As one specific example which will be discussed below in further detail,the media agent 144 can act as a local cache of copied data and/ormetadata that it has stored to the secondary storage device(s) 108,providing improved restore capabilities.

Generally speaking, a media agent 144 may be implemented as a softwaremodule that manages, coordinates, and facilitates the transmission ofdata, as directed by the storage manager 140, between a client computingdevice 102 and one or more secondary storage devices 108. Whereas thestorage manager 140 controls the operation of the information managementsystem 100, the media agent 144 generally provides a portal to secondarystorage devices 108.

Media agents 144 can comprise logically and/or physically separate nodesin the information management system 100 (e.g., separate from the clientcomputing devices 102, storage manager 140, and/or secondary storagedevices 108). In addition, each media agent 144 may reside on adedicated secondary storage computing device 106 in some cases, while inother embodiments a plurality of media agents 144 reside on the samesecondary storage computing device 106.

A media agent 144 (and corresponding media agent database 152) may beconsidered to be “associated with” a particular secondary storage device108 if that media agent 144 is capable of one or more of: routing and/orstoring data to the particular secondary storage device 108,coordinating the routing and/or storing of data to the particularsecondary storage device 108, retrieving data from the particularsecondary storage device 108, and coordinating the retrieval of datafrom a particular secondary storage device 108.

While media agent(s) 144 are generally associated with one or moresecondary storage devices 108, the media agents 144 in certainembodiments are physically separate from the secondary storage devices108. For instance, the media agents 144 may reside on secondary storagecomputing devices 106 having different housings or packages than thesecondary storage devices 108. In one example, a media agent 144 resideson a first server computer and is in communication with a secondarystorage device(s) 108 residing in a separate, rack-mounted RAID-basedsystem.

In operation, a media agent 144 associated with a particular secondarystorage device 108 may instruct the secondary storage device 108 (e.g.,a tape library) to use a robotic arm or other retrieval means to load oreject a certain storage media, and to subsequently archive, migrate, orretrieve data to or from that media, e.g., for the purpose of restoringthe data to a client computing device 102. The media agent 144 maycommunicate with a secondary storage device 108 via a suitablecommunications link, such as a SCSI or Fiber Channel link.

As shown, each media agent 144 may maintain an associated media agentdatabase 152. The media agent database 152 may be stored in a disk orother storage device (not shown) that is local to the secondary storagecomputing device 106 on which the media agent 144 resides. In othercases, the media agent database 152 is stored remotely from thesecondary storage computing device 106.

The media agent database 152 can include, among other things, an index153 including data generated during secondary copy operations and otherstorage or information management operations. The index 153 provides amedia agent 144 or other component with a fast and efficient mechanismfor locating secondary copies 116 or other data stored in the secondarystorage devices 108. In one configuration, a storage manager index 150or other data structure may store data associating a client computingdevice 102 with a particular media agent 144 and/or secondary storagedevice 108, as specified in a storage policy. A media agent index 153 orother data structure associated with the particular media agent 144 mayin turn include information about the stored data.

For instance, for each secondary copy 116, the index 153 may includemetadata such as a list of the data objects (e.g., files/subdirectories,database objects, mailbox objects, etc.), a path to the secondary copy116 on the corresponding secondary storage device 108, locationinformation indicating where the data objects are stored in thesecondary storage device 108, when the data objects were created ormodified, etc. Thus, the index 153 includes metadata associated with thesecondary copies 116 that is readily available for use in storageoperations and other activities without having to be first retrievedfrom the secondary storage device 108. In yet further embodiments, someor all of the data in the index 153 may instead or additionally bestored along with the data in a secondary storage device 108, e.g., witha copy of the index 153.

Because the index 153 maintained in the database 152 may operate as acache, it can also be referred to as an index cache. In such cases,information stored in the index cache 153 typically comprises data thatreflects certain particulars about storage operations that have occurredrelatively recently. After some triggering event, such as after acertain period of time elapses, or the index cache 153 reaches aparticular size, the index cache 153 may be copied or migrated to asecondary storage device(s) 108. This information may need to beretrieved and uploaded back into the index cache 153 or otherwiserestored to a media agent 144 to facilitate retrieval of data from thesecondary storage device(s) 108. In some embodiments, the cachedinformation may include format or containerization information relatedto archives or other files stored on the storage device(s) 108. In thismanner, the index cache 153 allows for accelerated restores.

In some alternative embodiments the media agent 144 generally acts as acoordinator or facilitator of storage operations between clientcomputing devices 102 and corresponding secondary storage devices 108,but does not actually write the data to the secondary storage device108. For instance, the storage manager 140 (or the media agent 144) mayinstruct a client computing device 102 and secondary storage device 108to communicate with one another directly. In such a case the clientcomputing device 102 transmits the data directly to the secondarystorage device 108 according to the received instructions, and viceversa. In some such cases, the media agent 144 may still receive,process, and/or maintain metadata related to the storage operations.Moreover, in these embodiments, the payload data can flow through themedia agent 144 for the purposes of populating the index cache 153maintained in the media agent database 152, but not for writing to thesecondary storage device 108.

The media agent 144 and/or other components such as the storage manager140 may in some cases incorporate additional functionality, such as dataclassification, content indexing, deduplication, encryption,compression, and the like. Further details regarding these and otherfunctions are described below.

Distributed, Scalable Architecture

As described, certain functions of the information management system 100can be distributed amongst various physical and/or logical components inthe system. For instance, one or more of the storage manager 140, dataagents 142, and media agents 144 may reside on computing devices thatare physically separate from one another. This architecture can providea number of benefits.

For instance, hardware and software design choices for each distributedcomponent can be targeted to suit its particular function. The secondarycomputing devices 106 on which the media agents 144 reside can betailored for interaction with associated secondary storage devices 108and provide fast index cache operation, among other specific tasks.Similarly, the client computing device(s) 102 can be selected toeffectively service the applications 110 residing thereon, in order toefficiently produce and store primary data 112.

Moreover, in some cases, one or more of the individual components in theinformation management system 100 can be distributed to multiple,separate computing devices. As one example, for large file systems wherethe amount of data stored in the storage management database 146 isrelatively large, the management database 146 may be migrated to orotherwise reside on a specialized database server (e.g., an SQL server)separate from a server that implements the other functions of thestorage manager 140. This configuration can provide added protectionbecause the database 146 can be protected with standard databaseutilities (e.g., SQL log shipping or database replication) independentfrom other functions of the storage manager 140. The database 146 can beefficiently replicated to a remote site for use in the event of adisaster or other data loss incident at the primary site. Or thedatabase 146 can be replicated to another computing device within thesame site, such as to a higher performance machine in the event that astorage manager host device can no longer service the needs of a growinginformation management system 100.

The distributed architecture also provides both scalability andefficient component utilization. FIG. 1D shows an embodiment of theinformation management system 100 including a plurality of clientcomputing devices 102 and associated data agents 142 as well as aplurality of secondary storage computing devices 106 and associatedmedia agents 144.

Additional components can be added or subtracted based on the evolvingneeds of the information management system 100. For instance, dependingon where bottlenecks are identified, administrators can add additionalclient computing devices 102, secondary storage devices 106 (andcorresponding media agents 144), and/or secondary storage devices 108.

Moreover, each client computing device 102 in some embodiments cancommunicate with any of the media agents 144, e.g., as directed by thestorage manager 140. And each media agent 144 may be able to communicatewith any of the secondary storage devices 108, e.g., as directed by thestorage manager 140. Thus, operations can be routed to the secondarystorage devices 108 in a dynamic and highly flexible manner. Furtherexamples of scalable systems capable of dynamic storage operations areprovided in U.S. Pat. No. 7,246,207, which is incorporated by referenceherein.

In alternative configurations, certain components are not distributedand may instead reside and execute on the same computing device. Forexample, in some embodiments one or more data agents 142 and the storagemanager 140 reside on the same client computing device 102. In anotherembodiment, one or more data agents 142 and one or more media agents 144reside on a single computing device.

Exemplary Types of Information Management Operations

In order to protect and leverage stored data, the information managementsystem 100 can be configured to perform a variety of informationmanagement operations. As will be described, these operations cangenerally include secondary copy and other data movement operations,processing and data manipulation operations, and management operations.

Data Movement Operations

Data movement operations according to certain embodiments are generallyoperations that involve the copying or migration of data (e.g., payloaddata) between different locations in the information management system100. For example, data movement operations can include operations inwhich stored data is copied, migrated, or otherwise transferred fromprimary storage device(s) 104 to secondary storage device(s) 108, fromsecondary storage device(s) 108 to different secondary storage device(s)108, or from primary storage device(s) 104 to different primary storagedevice(s) 104.

Data movement operations can include by way of example, backupoperations, archive operations, information lifecycle managementoperations such as hierarchical storage management operations,replication operations (e.g., continuous data replication operations),snapshot operations, deduplication operations, single-instancingoperations, auxiliary copy operations, and the like. As will bediscussed, some of these operations involve the copying, migration orother movement of data, without actually creating multiple, distinctcopies. Nonetheless, some or all of these operations are referred to as“copy” operations for simplicity.

Backup Operations

A backup operation creates a copy of primary data 112 at a particularpoint in time. Each subsequent backup copy may be maintainedindependently of the first. Further, a backup copy in some embodimentsis stored in a backup format. This can be in contrast to the version inprimary data 112 from which the backup copy is derived, and which mayinstead be stored in a native format of the source application(s) 110.In various cases, backup copies can be stored in a format in which thedata is compressed, encrypted, deduplicated, and/or otherwise modifiedfrom the original application format. For example, a backup copy may bestored in a backup format that facilitates compression and/or efficientlong-term storage.

Backup copies can have relatively long retention periods as compared toprimary data 112, and may be stored on media with slower retrieval timesthan primary data 112 and certain other types of secondary copies 116.On the other hand, backups may have relatively shorter retention periodsthan some other types of secondary copies 116, such as archive copies(described below). Backups may sometimes be stored at on offsitelocation.

Backup operations can include full, synthetic or incremental backups. Afull backup in some embodiments is generally a complete image of thedata to be protected. However, because full backup copies can consume arelatively large amount of storage, it can be useful to use a fullbackup copy as a baseline and only store changes relative to the fullbackup copy for subsequent backup copies.

For instance, a differential backup operation (or cumulative incrementalbackup operation) tracks and stores changes that have occurred since thelast full backup. Differential backups can grow quickly in size, but canprovide relatively efficient restore times because a restore can becompleted in some cases using only the full backup copy and the latestdifferential copy.

An incremental backup operation generally tracks and stores changessince the most recent backup copy of any type, which can greatly reducestorage utilization. In some cases, however, restore times can berelatively long in comparison to full or differential backups becausecompleting a restore operation may involve accessing a full backup inaddition to multiple incremental backups.

Any of the above types of backup operations can be at the file-level,e.g., where the information management system 100 generally trackschanges to files at the file-level, and includes copies of files in thebackup copy. In other cases, block-level backups are employed, wherefiles are broken into constituent blocks, and changes are tracked at theblock-level. Upon restore, the information management system 100reassembles the blocks into files in a transparent fashion.

Far less data may actually be transferred and copied to the secondarystorage devices 108 during a block-level copy than during a file-levelcopy, resulting in faster execution times. However, when restoring ablock-level copy, the process of locating constituent blocks cansometimes result in longer restore times as compared to file-levelbackups. Similar to backup operations, the other types of secondary copyoperations described herein can also be implemented at either thefile-level or the block-level.

Archive Operations

Because backup operations generally involve maintaining a version of thecopied data in primary data 112 and also maintaining backup copies insecondary storage device(s) 108, they can consume significant storagecapacity. To help reduce storage consumption, an archive operationaccording to certain embodiments creates a secondary copy 116 by bothcopying and removing source data. Or, seen another way, archiveoperations can involve moving some or all of the source data to thearchive destination. Thus, data satisfying criteria for removal (e.g.,data of a threshold age or size) from the source copy may be removedfrom source storage. Archive copies are sometimes stored in an archiveformat or other non-native application format. The source data may beprimary data 112 or a secondary copy 116, depending on the situation. Aswith backup copies, archive copies can be stored in a format in whichthe data is compressed, encrypted, deduplicated, and/or otherwisemodified from the original application format.

In addition, archive copies may be retained for relatively long periodsof time (e.g., years) and, in some cases, are never deleted. Archivecopies are generally retained for longer periods of time than backupcopies, for example. In certain embodiments, archive copies may be madeand kept for extended periods in order to meet compliance regulations.

Moreover, when primary data 112 is archived, in some cases the archivedprimary data 112 or a portion thereof is deleted when creating thearchive copy. Thus, archiving can serve the purpose of freeing up spacein the primary storage device(s) 104. Similarly, when a secondary copy116 is archived, the secondary copy 116 may be deleted, and an archivecopy can therefore serve the purpose of freeing up space in secondarystorage device(s) 108. In contrast, source copies often remain intactwhen creating backup copies.

Snapshot Operations

Snapshot operations can provide a relatively lightweight, efficientmechanism for protecting data. From an end-user viewpoint, a snapshotmay be thought of as an “instant” image of the primary data 112 at agiven point in time. In one embodiment, a snapshot may generally capturethe directory structure of an object in primary data 112 such as a fileor volume or other data set at a particular moment in time and may alsopreserve file attributes and contents. A snapshot in some cases iscreated relatively quickly, e.g., substantially instantly, using aminimum amount of file space, but may still function as a conventionalfile system backup.

A snapshot copy in many cases can be made quickly and withoutsignificantly impacting primary computing resources because largeamounts of data need not be copied or moved. In some embodiments, asnapshot may exist as a virtual file system, parallel to the actual filesystem. Users in some cases gain read-only access to the record of filesand directories of the snapshot. By electing to restore primary data 112from a snapshot taken at a given point in time, users may also returnthe current file system to the state of the file system that existedwhen the snapshot was taken.

Some types of snapshots do not actually create another physical copy ofall the data as it existed at the particular point in time, but maysimply create pointers that are able to map files and directories tospecific memory locations (e.g., disk blocks) where the data resides, asit existed at the particular point in time. For example, a snapshot copymay include a set of pointers derived from the file system or anapplication. Each pointer points to a respective stored data block, socollectively, the set of pointers reflect the storage location and stateof the data object (e.g., file(s) or volume(s) or data set(s)) at aparticular point in time when the snapshot copy was created.

In some embodiments, once a snapshot has been taken, subsequent changesto the file system typically do not overwrite the blocks in use at thetime of the snapshot. Therefore, the initial snapshot may use only asmall amount of disk space needed to record a mapping or other datastructure representing or otherwise tracking the blocks that correspondto the current state of the file system. Additional disk space isusually required only when files and directories are actually modifiedlater. Furthermore, when files are modified, typically only the pointerswhich map to blocks are copied, not the blocks themselves. In someembodiments, for example in the case of “copy-on-write” snapshots, whena block changes in primary storage, the block is copied to secondarystorage or cached in primary storage before the block is overwritten inprimary storage. The snapshot mapping of file system data is alsoupdated to reflect the changed block(s) at that particular point intime. In some other cases, a snapshot includes a full physical copy ofall or substantially all of the data represented by the snapshot.Further examples of snapshot operations are provided in U.S. Pat. No.7,529,782, which is incorporated by reference herein.

Replication Operations

Another type of secondary copy operation is a replication operation.Some types of secondary copies 116 are used to periodically captureimages of primary data 112 at particular points in time (e.g., backups,archives, and snapshots). However, it can also be useful for recoverypurposes to protect primary data 112 in a more continuous fashion, byreplicating the primary data 112 substantially as changes occur. In somecases a replication copy can be a mirror copy, for instance, wherechanges made to primary data 112 are mirrored to another location (e.g.,to secondary storage device(s) 108). By copying each write operation tothe replication copy, two storage systems are kept synchronized orsubstantially synchronized so that they are virtually identical atapproximately the same time. Where entire disk volumes are mirrored,however, mirroring can require significant amount of storage space andutilizes a large amount of processing resources.

According to some embodiments storage operations are performed onreplicated data that represents a recoverable state, or “known goodstate” of a particular application running on the source system. Forinstance, in certain embodiments, known good replication copies may beviewed as copies of primary data 112. This feature allows the system todirectly access, copy, restore, backup or otherwise manipulate thereplication copies as if the data was the “live”, primary data 112. Thiscan reduce access time, storage utilization, and impact on sourceapplications 110, among other benefits.

Based on known good state information, the information management system100 can replicate sections of application data that represent arecoverable state rather than rote copying of blocks of data. Examplesof compatible replication operations (e.g., continuous data replication)are provided in U.S. Pat. No. 7,617,262, which is incorporated byreference herein.

Deduplication/Single-Instancing Operations

Another type of data movement operation is deduplication, which isuseful to reduce the amount of data within the system. For instance,some or all of the above-described secondary storage operations caninvolve deduplication in some fashion. New data is read, broken downinto blocks (e.g., sub-file level blocks) of a selected granularity,compared with blocks that are already stored, and only the new blocksare stored. Blocks that already exist are represented as pointers to thealready stored data.

In order to stream-line the comparison process, the informationmanagement system 100 may calculate and/or store signatures (e.g.,hashes) corresponding to the individual data blocks and compare thehashes instead of comparing entire data blocks. In some cases, only asingle instance of each element is stored, and deduplication operationsmay therefore be referred to interchangeably as “single-instancing”operations. Depending on the implementation, however, deduplication orsingle-instancing operations can store more than one instance of certaindata blocks, but nonetheless significantly reduce data redundancy.Moreover, single-instancing in some cases is distinguished fromdeduplication as a process of analyzing and reducing data at the filelevel, rather than the sub-file level.

Depending on the embodiment, deduplication blocks can be of fixed orvariable length. Using variable length blocks can provide enhanceddeduplication by responding to changes in the data stream, but caninvolve complex processing. In some cases, the information managementsystem 100 utilizes a technique for dynamically aligning deduplicationblocks (e.g., fixed-length blocks) based on changing content in the datastream, as described in U.S. Pat. Pub. No. 2012/0084269, which isincorporated by reference herein.

The information management system 100 can perform deduplication in avariety of manners at a variety of locations in the informationmanagement system 100. For instance, in some embodiments, theinformation management system 100 implements “target-side” deduplicationby deduplicating data (e.g., secondary copies 116) stored in thesecondary storage devices 108. In some such cases, the media agents 144are generally configured to manage the deduplication process. Forinstance, one or more of the media agents 144 maintain a correspondingdeduplication database that stores deduplication information (e.g.,datablock signatures). Examples of such a configuration are provided inU.S. Pat. Pub. No. 2012/0150826, which is incorporated by referenceherein. Deduplication can also be performed on the “source-side” (or“client-side”), e.g., to reduce the amount of traffic between the mediaagents 144 and the client computing device(s) 102 and/or reduceredundant data stored in the primary storage devices 104. Examples ofsuch deduplication techniques are provided in U.S. Pat. Pub. No.2012/0150818, which is incorporated by reference herein.

Information Lifecycle Management and Hierarchical Storage ManagementOperations

In some embodiments, files and other data over their lifetime move frommore expensive, quick access storage to less expensive, slower accessstorage. Operations associated with moving data through various tiers ofstorage are sometimes referred to as information lifecycle management(ILM) operations.

One type of ILM operation is a hierarchical storage management (HSM)operation. A HSM operation is generally an operation for automaticallymoving data between classes of storage devices, such as betweenhigh-cost and low-cost storage devices. For instance, an HSM operationmay involve movement of data from primary storage devices 104 tosecondary storage devices 108, or between tiers of secondary storagedevices 108. With each tier, the storage devices may be progressivelyrelatively cheaper, have relatively slower access/restore times, etc.For example, movement of data between tiers may occur as data becomesless important over time.

In some embodiments, an HSM operation is similar to an archive operationin that creating an HSM copy may (though not always) involve deletingsome of the source data. For example, an HSM copy may include data fromprimary data 112 or a secondary copy 116 that is larger than a givensize threshold or older than a given age threshold and that is stored ina backup format.

Often, and unlike some types of archive copies, HSM data that is removedor aged from the source copy is replaced by a logical reference pointeror stub. The reference pointer or stub can be stored in the primarystorage device 104 to replace the deleted data in primary data 112 (orother source copy) and to point to or otherwise indicate the newlocation in a secondary storage device 108.

According to one example, files are generally moved between higher andlower cost storage depending on how often the files are accessed. When auser requests access to the HSM data that has been removed or migrated,the information management system 100 uses the stub to locate the dataand often make recovery of the data appear transparent, even though theHSM data may be stored at a location different from the remaining sourcedata. The stub may also include some metadata associated with thecorresponding data, so that a file system and/or application can providesome information about the data object and/or a limited-functionalityversion (e.g., a preview) of the data object.

An HSM copy may be stored in a format other than the native applicationformat (e.g., where the data is compressed, encrypted, deduplicated,and/or otherwise modified from the original application format). In somecases, copies which involve the removal of data from source storage andthe maintenance of stub or other logical reference information on sourcestorage may be referred to generally as “on-line archive copies”. On theother hand, copies which involve the removal of data from source storagewithout the maintenance of stub or other logical reference informationon source storage may be referred to as “off-line archive copies”.

Auxiliary Copy and Disaster Recovery Operations

An auxiliary copy is generally a copy operation in which a copy iscreated of an existing secondary copy 116. For instance, an initial or“primary” secondary copy 116 may be generated using or otherwise bederived from primary data 112, whereas an auxiliary copy is generatedfrom the initial secondary copy 116. Auxiliary copies can be used tocreate additional standby copies of data and may reside on differentsecondary storage devices 108 than initial secondary copies 116. Thus,auxiliary copies can be used for recovery purposes if initial secondarycopies 116 become unavailable. Exemplary compatible auxiliary copytechniques are described in further detail in U.S. Pat. No. 8,230,195,which is incorporated by reference herein.

The information management system 100 may also perform disaster recoveryoperations that make or retain disaster recovery copies, often assecondary, high-availability disk copies. The information managementsystem 100 may create secondary disk copies and store the copies atdisaster recovery locations using auxiliary copy or replicationoperations, such as continuous data replication technologies. Dependingon the particular data protection goals, disaster recovery locations canbe remote from the client computing devices 102 and primary storagedevices 104, remote from some or all of the secondary storage devices108, or both.

Data Processing and Manipulation Operations

As indicated, the information management system 100 can also beconfigured to implement certain data manipulation operations, whichaccording to certain embodiments are generally operations involving theprocessing or modification of stored data. Some data manipulationoperations include content indexing operations and classificationoperations can be useful in leveraging the data under management toprovide enhanced search and other features. Other data manipulationoperations such as compression and encryption can provide data reductionand security benefits, respectively.

Data manipulation operations can be different than data movementoperations in that they do not necessarily involve the copying,migration or other transfer of data (e.g., primary data 112 or secondarycopies 116) between different locations in the system. For instance,data manipulation operations may involve processing (e.g., offlineprocessing) or modification of already stored primary data 112 and/orsecondary copies 116. However, in some embodiments data manipulationoperations are performed in conjunction with data movement operations.As one example, the information management system 100 may encrypt datawhile performing an archive operation.

Content Indexing

In some embodiments, the information management system 100 “contentindexes” data stored within the primary data 112 and/or secondary copies116, providing enhanced search capabilities for data discovery and otherpurposes. The content indexing can be used to identify files or otherdata objects having pre-defined content (e.g., user-defined keywords orphrases), metadata (e.g., email metadata such as “to”, “from”, “cc”,“bcc”, attachment name, received time, etc.).

The information management system 100 generally organizes and cataloguesthe results in a content index, which may be stored within the mediaagent database 152, for example. The content index can also include thestorage locations of (or pointer references to) the indexed data in theprimary data 112 or secondary copies 116, as appropriate. The resultsmay also be stored, in the form of a content index database orotherwise, elsewhere in the information management system 100 (e.g., inthe primary storage devices 104, or in the secondary storage device108). Such index data provides the storage manager 140 or anothercomponent with an efficient mechanism for locating primary data 112and/or secondary copies 116 of data objects that match particularcriteria.

For instance, search criteria can be specified by a user through userinterface 158 of the storage manager 140. In some cases, the informationmanagement system 100 analyzes data and/or metadata in secondary copies116 to create an “off-line” content index, without significantlyimpacting the performance of the client computing devices 102. Dependingon the embodiment, the system can also implement “on-line” contentindexing, e.g., of primary data 112. Examples of compatible contentindexing techniques are provided in U.S. Pat. No. 8,170,995, which isincorporated by reference herein.

Classification Operations—Metabase

In order to help leverage the data stored in the information managementsystem 100, one or more components can be configured to scan data and/orassociated metadata for classification purposes to populate a metabaseof information. Such scanned, classified data and/or metadata may beincluded in a separate database and/or on a separate storage device fromprimary data 112 (and/or secondary copies 116), such that metabaserelated operations do not significantly impact performance on othercomponents in the information management system 100.

In other cases, the metabase(s) may be stored along with primary data112 and/or secondary copies 116. Files or other data objects can beassociated with user-specified identifiers (e.g., tag entries) in themedia agent 144 (or other indices) to facilitate searches of stored dataobjects. Among a number of other benefits, the metabase can also allowefficient, automatic identification of files or other data objects toassociate with secondary copy or other information management operations(e.g., in lieu of scanning an entire file system). Examples ofcompatible metabases and data classification operations are provided inU.S. Pat. Nos. 8,229,954 and 7,747,579, which are incorporated byreference herein.

Encryption Operations

The information management system 100 in some cases is configured toprocess data (e.g., files or other data objects, secondary copies 116,etc.), according to an appropriate encryption algorithm (e.g., Blowfish,Advanced Encryption Standard [AES], Triple Data Encryption Standard[3-DES], etc.) to limit access and provide data security in theinformation management system 100.

The information management system 100 in some cases encrypts the data atthe client level, such that the client computing devices 102 (e.g., thedata agents 142) encrypt the data prior to forwarding the data to othercomponents, e.g., before sending the data media agents 144 during asecondary copy operation. In such cases, the client computing device 102may maintain or have access to an encryption key or passphrase fordecrypting the data upon restore. Encryption can also occur whencreating copies of secondary copies, e.g., when creating auxiliarycopies. In yet further embodiments, the secondary storage devices 108can implement built-in, high performance hardware encryption.

Management Operations

Certain embodiments leverage the integrated, ubiquitous nature of theinformation management system 100 to provide useful system-widemanagement functions. As two non-limiting examples, the informationmanagement system 100 can be configured to implement operationsmanagement and e-discovery functions.

Operations management can generally include monitoring and managing thehealth and performance of information management system 100 by, withoutlimitation, performing error tracking, generating granularstorage/performance metrics (e.g., job success/failure information,deduplication efficiency, etc.), generating storage modeling and costinginformation, and the like.

Such information can be provided to users via the user interface 158 ina single, integrated view. For instance, the integrated user interface158 can include an option to show a “virtual view” of the system thatgraphically depicts the various components in the system usingappropriate icons. The operations management functionality canfacilitate planning and decision-making. For example, in someembodiments, a user may view the status of some or all jobs as well asthe status of each component of the information management system 100.Users may then plan and make decisions based on this data. For instance,a user may view high-level information regarding storage operations forthe information management system 100, such as job status, componentstatus, resource status (e.g., network pathways, etc.), and otherinformation. The user may also drill down or use other means to obtainmore detailed information regarding a particular component, job, or thelike.

In some cases the information management system 100 alerts a user suchas a system administrator when a particular resource is unavailable orcongested. For example, a particular primary storage device 104 orsecondary storage device 108 might be full or require additionalcapacity. Or a component may be unavailable due to hardware failure,software problems, or other reasons. In response, the informationmanagement system 100 may suggest solutions to such problems when theyoccur (or provide a warning prior to occurrence). For example, thestorage manager 140 may alert the user that a secondary storage device108 is full or otherwise congested. The storage manager 140 may thensuggest, based on job and data storage information contained in itsdatabase 146, an alternate secondary storage device 108.

Other types of corrective actions may include suggesting an alternatedata path to a particular primary or secondary storage device 104, 108,or dividing data to be stored among various available primary orsecondary storage devices 104, 108 as a load balancing measure or tootherwise optimize storage or retrieval time. Such suggestions orcorrective actions may be performed automatically, if desired. Furtherexamples of some compatible operations management techniques and ofinterfaces providing an integrated view of an information managementsystem are provided in U.S. Pat. No. 7,343,453, which is incorporated byreference herein. In some embodiments, the storage manager 140implements the operations management functions described herein.

The information management system 100 can also be configured to performsystem-wide e-discovery operations in some embodiments. In general,e-discovery operations provide a unified collection and searchcapability for data in the system, such as data stored in the secondarystorage devices 108 (e.g., backups, archives, or other secondary copies116). For example, the information management system 100 may constructand maintain a virtual repository for data stored in the informationmanagement system 100 that is integrated across source applications 110,different storage device types, etc. According to some embodiments,e-discovery utilizes other techniques described herein, such as dataclassification and/or content indexing.

Information Management Policies

As indicated previously, an information management policy 148 caninclude a data structure or other information source that specifies aset of parameters (e.g., criteria and rules) associated with secondarycopy or other information management operations.

One type of information management policy 148 is a storage policy.According to certain embodiments, a storage policy generally comprises alogical container that defines (or includes information sufficient todetermine) one or more of the following items: (1) what data will beassociated with the storage policy; (2) a destination to which the datawill be stored; (3) datapath information specifying how the data will becommunicated to the destination; (4) the type of storage operation to beperformed; and (5) retention information specifying how long the datawill be retained at the destination.

Data associated with a storage policy can be logically organized intogroups, which can be referred to as “sub-clients”. A sub-client mayrepresent static or dynamic associations of portions of a data volume.Sub-clients may represent mutually exclusive portions. Thus, in certainembodiments, a portion of data may be given a label and the associationis stored as a static entity in an index, database or other storagelocation.

Sub-clients may also be used as an effective administrative scheme oforganizing data according to data type, department within theenterprise, storage preferences, or the like. Depending on theconfiguration, sub-clients can correspond to files, folders, virtualmachines, databases, etc. In one exemplary scenario, an administratormay find it preferable to separate e-mail data from financial data usingtwo different sub-clients.

A storage policy can define where data is stored by specifying a targetor destination storage device (or group of storage devices). Forinstance, where the secondary storage device 108 includes a group ofdisk libraries, the storage policy may specify a particular disk libraryfor storing the sub-clients associated with the policy. As anotherexample, where the secondary storage devices 108 include one or moretape libraries, the storage policy may specify a particular tape libraryfor storing the sub-clients associated with the storage policy, and mayalso specify a drive pool and a tape pool defining a group of tapedrives and a group of tapes, respectively, for use in storing thesub-client data.

Datapath information can also be included in the storage policy. Forinstance, the storage policy may specify network pathways and componentsto utilize when moving the data to the destination storage device(s). Insome embodiments, the storage policy specifies one or more media agents144 for conveying data (e.g., one or more sub-clients) associated withthe storage policy between the source (e.g., one or more host clientcomputing devices 102) and destination (e.g., a particular targetsecondary storage device 108).

A storage policy can also specify the type(s) of operations associatedwith the storage policy, such as a backup, archive, snapshot, auxiliarycopy, or the like. Retention information can specify how long the datawill be kept, depending on organizational needs (e.g., a number of days,months, years, etc.)

The information management policies 148 may also include one or morescheduling policies specifying when and how often to perform operations.Scheduling information may specify with what frequency (e.g., hourly,weekly, daily, event-based, etc.) or under what triggering conditionssecondary copy or other information management operations will takeplace. Scheduling policies in some cases are associated with particularcomponents, such as particular sub-clients, client computing device 102,and the like. In one configuration, a separate scheduling policy ismaintained for particular sub-clients on a client computing device 102.The scheduling policy specifies that those sub-clients are to be movedto secondary storage devices 108 every hour according to storagepolicies associated with the respective sub-clients.

When adding a new client computing device 102, administrators canmanually configure information management policies 148 and/or othersettings, e.g., via the user interface 158. However, this can be aninvolved process resulting in delays, and it may be desirable to begindata protecting operations quickly.

Thus, in some embodiments, the information management system 100automatically applies a default configuration to client computing device102. As one example, when a data agent(s) 142 is installed on a clientcomputing devices 102, the installation script may register the clientcomputing device 102 with the storage manager 140, which in turn appliesthe default configuration to the new client computing device 102. Inthis manner, data protection operations can begin substantiallyimmediately. The default configuration can include a default storagepolicy, for example, and can specify any appropriate informationsufficient to begin data protection operations. This can include a typeof data protection operation, scheduling information, a target secondarystorage device 108, data path information (e.g., a particular mediaagent 144), and the like.

Other types of information management policies 148 are possible. Forinstance, the information management policies 148 can also include oneor more audit or security policies. An audit policy is a set ofpreferences, rules and/or criteria that protect sensitive data in theinformation management system 100. For example, an audit policy maydefine “sensitive objects” as files or objects that contain particularkeywords (e.g. “confidential,” or “privileged”) and/or are associatedwith particular keywords (e.g., in metadata) or particular flags (e.g.,in metadata identifying a document or email as personal, confidential,etc.).

An audit policy may further specify rules for handling sensitiveobjects. As an example, an audit policy may require that a reviewerapprove the transfer of any sensitive objects to a cloud storage site,and that if approval is denied for a particular sensitive object, thesensitive object should be transferred to a local storage device 104instead. To facilitate this approval, the audit policy may furtherspecify how a secondary storage computing device 106 or other systemcomponent should notify a reviewer that a sensitive object is slated fortransfer.

In some implementations, the information management policies 148 mayinclude one or more provisioning policies. A provisioning policy caninclude a set of preferences, priorities, rules, and/or criteria thatspecify how clients 102 (or groups thereof) may utilize systemresources, such as available storage on cloud storage and/or networkbandwidth. A provisioning policy specifies, for example, data quotas forparticular client computing devices 102 (e.g. a number of gigabytes thatcan be stored monthly, quarterly or annually). The storage manager 140or other components may enforce the provisioning policy. For instance,the media agents 144 may enforce the policy when transferring data tosecondary storage devices 108. If a client computing device 102 exceedsa quota, a budget for the client computing device 102 (or associateddepartment) is adjusted accordingly or an alert may trigger.

While the above types of information management policies 148 have beendescribed as separate policies, one or more of these can be generallycombined into a single information management policy 148. For instance,a storage policy may also include or otherwise be associated with one ormore scheduling, audit, or provisioning policies. Moreover, whilestorage policies are typically associated with moving and storing data,other policies may be associated with other types of informationmanagement operations. The following is a non-exhaustive list of itemsthe information management policies 148 may specify:

-   -   schedules or other timing information, e.g., specifying when        and/or how often to perform information management operations;    -   the type of secondary copy 116 and/or secondary copy format        (e.g., snapshot, backup, archive, HSM, etc.);    -   a location or a class or quality of storage for storing        secondary copies 116 (e.g., one or more particular secondary        storage devices 108);    -   preferences regarding whether and how to encrypt, compress,        deduplicate, or otherwise modify or transform secondary copies        116;    -   which system components and/or network pathways (e.g., preferred        media agents 144) should be used to perform secondary storage        operations;    -   resource allocation between different computing devices or other        system components used in performing information management        operations (e.g., bandwidth allocation, available storage        capacity, etc.);    -   whether and how to synchronize or otherwise distribute files or        other data objects across multiple computing devices or hosted        services; and    -   retention information specifying the length of time primary data        112 and/or secondary copies 116 should be retained, e.g., in a        particular class or tier of storage devices, or within the        information management system 100.

Policies can additionally specify or depend on a variety of historicalor current criteria that may be used to determine which rules to applyto a particular data object, system component, or information managementoperation, such as:

-   -   frequency with which primary data 112 or a secondary copy 116 of        a data object or metadata has been or is predicted to be used,        accessed, or modified;    -   time-related factors (e.g., aging information such as time since        the creation or modification of a data object);    -   deduplication information (e.g., hashes, data blocks,        deduplication block size, deduplication efficiency or other        metrics);    -   an estimated or historic usage or cost associated with different        components (e.g., with secondary storage devices 108);    -   the identity of users, applications 110, client computing        devices 102 and/or other computing devices that created,        accessed, modified, or otherwise utilized primary data 112 or        secondary copies 116;    -   a relative sensitivity (e.g., confidentiality) of a data object,        e.g., as determined by its content and/or metadata;    -   the current or historical storage capacity of various storage        devices;    -   the current or historical network capacity of network pathways        connecting various components within the storage operation cell;    -   access control lists or other security information; and    -   the content of a particular data object (e.g., its textual        content) or of metadata associated with the data object.

Exemplary Storage Policy and Secondary Storage Operations

FIG. 1E shows a data flow data diagram depicting performance of storageoperations by an embodiment of an information management system 100,according to an exemplary data storage policy 148A. The informationmanagement system 100 includes a storage manger 140, a client computingdevice 102 having a file system data agent 142A and an email data agent142B residing thereon, a primary storage device 104, two media agents144A, 144B, and two secondary storage devices 108A, 108B: a disk library108A and a tape library 108B. As shown, the primary storage device 104includes primary data 112A, 112B associated with a file systemsub-client and an email sub-client, respectively.

As indicated by the dashed box, the second media agent 144B and the tapelibrary 108B are “off-site”, and may therefore be remotely located fromthe other components in the information management system 100 (e.g., ina different city, office building, etc.). In this manner, informationstored on the tape library 108B may provide protection in the event of adisaster or other failure.

The file system sub-client and its associated primary data 112A incertain embodiments generally comprise information generated by the filesystem and/or operating system of the client computing device 102, andcan include, for example, file system data (e.g., regular files, filetables, mount points, etc.), operating system data (e.g., registries,event logs, etc.), and the like. The e-mail sub-client, on the otherhand, and its associated primary data 112B, include data generated by ane-mail client application operating on the client computing device 102,and can include mailbox information, folder information, emails,attachments, associated database information, and the like. As describedabove, the sub-clients can be logical containers, and the data includedin the corresponding primary data 112A, 112B may or may not be storedcontiguously.

The exemplary storage policy 148A includes a backup copy rule set 160, adisaster recovery copy rule set 162, and a compliance copy rule set 164.The backup copy rule set 160 specifies that it is associated with a filesystem sub-client 166 and an email sub-client 168. Each of thesesub-clients 166, 168 are associated with the particular client computingdevice 102. The backup copy rule set 160 further specifies that thebackup operation will be written to the disk library 108A, anddesignates a particular media agent 144A to convey the data to the disklibrary 108A. Finally, the backup copy rule set 160 specifies thatbackup copies created according to the rule set 160 are scheduled to begenerated on an hourly basis and to be retained for 30 days. In someother embodiments, scheduling information is not included in the storagepolicy 148A, and is instead specified by a separate scheduling policy.

The disaster recovery copy rule set 162 is associated with the same twosub-clients 166, 168. However, the disaster recovery copy rule set 162is associated with the tape library 108B, unlike the backup copy ruleset 160. Moreover, the disaster recovery copy rule set 162 specifiesthat a different media agent 144B than the media agent 144A associatedwith the backup copy rule set 160 will be used to convey the data to thetape library 108B. As indicated, disaster recovery copies createdaccording to the rule set 162 will be retained for 60 days, and will begenerated on a daily basis. Disaster recovery copies generated accordingto the disaster recovery copy rule set 162 can provide protection in theevent of a disaster or other data-loss event that would affect thebackup copy 116A maintained on the disk library 108A.

The compliance copy rule set 164 is only associated with the emailsub-client 166, and not the file system sub-client 168. Compliancecopies generated according to the compliance copy rule set 164 willtherefore not include primary data 112A from the file system sub-client166. For instance, the organization may be under an obligation to storemaintain copies of email data for a particular period of time (e.g., 10years) to comply with state or federal regulations, while similarregulations do not apply to the file system data. The compliance copyrule set 164 is associated with the same tape library 108B and mediaagent 144B as the disaster recovery copy rule set 162, although adifferent storage device or media agent could be used in otherembodiments. Finally, the compliance copy rule set 164 specifies thatcopies generated under the compliance copy rule set 164 will be retainedfor 10 years, and will be generated on a quarterly basis.

At step 1, the storage manager 140 initiates a backup operationaccording to the backup copy rule set 160. For instance, a schedulingservice running on the storage manager 140 accesses schedulinginformation from the backup copy rule set 160 or a separate schedulingpolicy associated with the client computing device 102, and initiates abackup copy operation on an hourly basis. Thus, at the scheduled timeslot the storage manager 140 sends instructions to the client computingdevice 102 to begin the backup operation.

At step 2, the file system data agent 142A and the email data agent 142Bresiding on the client computing device 102 respond to the instructionsreceived from the storage manager 140 by accessing and processing theprimary data 112A, 112B involved in the copy operation from the primarystorage device 104. Because the operation is a backup copy operation,the data agent(s) 142A, 142B may format the data into a backup format orotherwise process the data.

At step 3, the client computing device 102 communicates the retrieved,processed data to the first media agent 144A, as directed by the storagemanager 140, according to the backup copy rule set 160. In some otherembodiments, the information management system 100 may implement aload-balancing, availability-based, or other appropriate algorithm toselect from the available set of media agents 144A, 144B. Regardless ofthe manner the media agent 144A is selected, the storage manager 140 mayfurther keep a record in the storage manager database 140 of theassociation between the selected media agent 144A and the clientcomputing device 102 and/or between the selected media agent 144A andthe backup copy 116A.

The target media agent 144A receives the data from the client computingdevice 102, and at step 4 conveys the data to the disk library 108A tocreate the backup copy 116A, again at the direction of the storagemanager 140 and according to the backup copy rule set 160. The secondarystorage device 108A can be selected in other ways. For instance, themedia agent 144A may have a dedicated association with a particularsecondary storage device(s), or the storage manager 140 or media agent144A may select from a plurality of secondary storage devices, e.g.,according to availability, using one of the techniques described in U.S.Pat. No. 7,246,207, which is incorporated by reference herein.

The media agent 144A can also update its index 153 to include dataand/or metadata related to the backup copy 116A, such as informationindicating where the backup copy 116A resides on the disk library 108A,data and metadata for cache retrieval, etc. After the 30 day retentionperiod expires, the storage manager 140 instructs the media agent 144Ato delete the backup copy 116A from the disk library 108A.

At step 5, the storage manager 140 initiates the creation of a disasterrecovery copy 116B according to the disaster recovery copy rule set 162.For instance, at step 6, based on instructions received from the storagemanager 140 at step 5, the specified media agent 144B retrieves the mostrecent backup copy 116A from the disk library 108A.

At step 7, again at the direction of the storage manager 140 and asspecified in the disaster recovery copy rule set 162, the media agent144B uses the retrieved data to create a disaster recovery copy 116B onthe tape library 108B. In some cases, the disaster recovery copy 116B isa direct, mirror copy of the backup copy 116A, and remains in the backupformat. In other embodiments, the disaster recovery copy 116C may begenerated in some other manner, such as by using the primary data 112A,112B from the storage device 104 as source data. The disaster recoverycopy operation is initiated once a day and the disaster recovery copies116A are deleted after 60 days.

At step 8, the storage manager 140 initiates the creation of acompliance copy 116C, according to the compliance copy rule set 164. Forinstance, the storage manager 140 instructs the media agent 144B tocreate the compliance copy 116C on the tape library 108B at step 9, asspecified in the compliance copy rule set 164. In the example, thecompliance copy 116C is generated using the disaster recovery copy 116B.In other embodiments, the compliance copy 116C is instead generatedusing either the primary data 112B corresponding to the email sub-clientor using the backup copy 116A from the disk library 108A as source data.As specified, compliance copies 116C are created quarterly, and aredeleted after ten years.

While not shown in FIG. 1E, at some later point in time, a restoreoperation can be initiated involving one or more of the secondary copies116A, 116B, 116C. As one example, a user may manually initiate a restoreof the backup copy 116A by interacting with the user interface 158 ofthe storage manager 140. The storage manager 140 then accesses data inits index 150 (and/or the respective storage policy 148A) associatedwith the selected backup copy 116A to identify the appropriate mediaagent 144A and/or secondary storage device 116A.

In other cases, a media agent may be selected for use in the restoreoperation based on a load balancing algorithm, an availability basedalgorithm, or other criteria. The selected media agent 144A retrievesthe data from the disk library 108A. For instance, the media agent 144Amay access its index 153 to identify a location of the backup copy 116Aon the disk library 108A, or may access location information residing onthe disk 108A itself.

When the backup copy 116A was recently created or accessed, the mediaagent 144A accesses a cached version of the backup copy 116A residing inthe media agent index 153, without having to access the disk library108A for some or all of the data. Once it has retrieved the backup copy116A, the media agent 144A communicates the data to the source clientcomputing device 102. Upon receipt, the file system data agent 142A andthe email data agent 142B may unpackage (e.g., restore from a backupformat to the native application format) the data in the backup copy116A and restore the unpackaged data to the primary storage device 104.

Exemplary Secondary Copy Formatting

The formatting and structure of secondary copies 116 can vary, dependingon the embodiment. In some cases, secondary copies 116 are formatted asa series of logical data units or “chunks” (e.g., 512 MB, 1 GB, 2 GB, 4GB, or 8 GB chunks). This can facilitate efficient communication andwriting to secondary storage devices 108, e.g., according to resourceavailability. For example, a single secondary copy 116 may be written ona chunk-by-chunk basis to a single secondary storage device 108 oracross multiple secondary storage devices 108. In some cases, users canselect different chunk sizes, e.g., to improve throughput to tapestorage devices.

Generally, each chunk can include a header and a payload. The payloadcan include files (or other data units) or subsets thereof included inthe chunk, whereas the chunk header generally includes metadata relatingto the chunk, some or all of which may be derived from the payload. Forexample, during a secondary copy operation, the media agent 144, storagemanager 140, or other component may divide the associated files intochunks and generate headers for each chunk by processing the constituentfiles.

The headers can include a variety of information such as fileidentifier(s), volume(s), offset(s), or other information associatedwith the payload data items, a chunk sequence number, etc. Importantly,in addition to being stored with the secondary copy 116 on the secondarystorage device 108, the chunk headers can also be stored to the index153 of the associated media agent(s) 144 and/or the storage managerindex 150. This is useful in some cases for providing faster processingof secondary copies 116 during restores or other operations. In somecases, once a chunk is successfully transferred to a secondary storagedevice 108, the secondary storage device 108 returns an indication ofreceipt, e.g., to the media agent 144 and/or storage manager 140, whichmay update their respective indexes 150, 153 accordingly.

During restore, chunks may be processed (e.g., by the media agent 144)according to the information in the chunk header to reassemble thefiles. Additional information relating to chunks can be found in U.S.Pat. No. 8,156,086, which is incorporated by reference herein.

Integrated Snapshot Interface

FIG. 2A shows a block diagram illustrative of embodiments of a networkedstorage system 200 in accordance with the principles of the presentdisclosure. As shown, storage system 200 may generally include a storagemanager 202 and one or more clients 218, destination storage devices216, media agents 234, and secondary storage devices 236. Examples ofmodular, scalable storage systems, include the CommVault Simpana system,CommVault QiNetix® system, and the CommVault GALAXY backup system,available from CommVault Systems, Inc. of Oceanport, N.J., and furtherdescribed in U.S. patent application Ser. Nos. 09/610,738 and10/818,749, now U.S. Pat. Nos. 7,035,880 and 7,246,207, which areincorporated herein by reference in their entirety.

The system 200 may be one of a plurality of storage operation cells, andgenerally includes combinations of hardware and software componentsassociated with performing storage operations on electronic data.According to some embodiments of the present disclosure, the storagesystem 200 is one of a plurality of backup cells which provide some orall of the functionality of backup cells as described in U.S. patentapplication Ser. No. 09/354,058, which is hereby incorporated byreference in its entirety. However, in certain embodiments, storageoperation cells also perform additional types of storage operations andother types of storage management functions, as will be describedherein.

In accordance with certain embodiments of the present disclosure,additional storage operations performed by the system 200 may includecreating, storing, retrieving, and migrating primary storage data (e.g.,the data stored in the information stores 220) and secondary storagedata which may include, for example, snapshot copies, backup copies,hierarchical storage management [HSM] copies, archive copies, and othertypes of copies of electronic data) stored on storage devices 236. Thedestination storage devices 216 can store primary storage data,secondary storage data, or both, depending on the embodiment. In someembodiments, storage operation system 200 also provides one or moreintegrated management consoles for users or system processes tointerface with in order to perform certain storage operations onelectronic data as further described herein. Such integrated managementconsoles may be displayed at a central control facility or severalsimilar consoles distributed throughout multiple network locations toprovide global or geographically specific network data storageinformation.

In some embodiments, storage operations may be performed according tovarious storage preferences, for example as expressed by a userpreference or storage policy. Exemplary storage policies are describedabove, and in some embodiments, a storage policy can be any of thestorage policies described above with respect to FIGS. 1C-E. A storagepolicy can generally a data structure or other information source thatincludes a set of preferences and other storage criteria associated withperforming a storage operation. The preferences and storage criteria mayinclude, but are not limited to, a storage location, relationshipsbetween system components, network pathway to utilize, retentionpolicies, data characteristics, compression or encryption requirements,preferred system components to utilize in a storage operation, othercriteria relating to a storage operation, combinations of the same andthe like. Thus, in certain embodiments, a storage policy may indicatethat certain data is to be stored in a specific storage device, retainedfor a specified period of time before being aged to another tier ofsecondary storage, copied to secondary storage using a specified numberof streams. A storage policy may be stored in the storage manager index208, in archive media as metadata for use in restore operations or otherstorage operations, or in other locations or components of the system.

In certain embodiments, the storage policy may specify when to performstorage operations and how often and may also specify performing certainstorage operations on sub-clients of data and how to treat thosesub-clients. A sub-client may represent static or dynamic associationsof portions of data of a volume and are typically mutually exclusive.Thus, in certain embodiments, a portion of data may be given a label andthe association is stored as a static entity in an index, database orother storage location used by the system. Sub-clients may also be usedas an effective administrative scheme of organizing data according todata type, department within the enterprise, storage preferences,combinations of the same or the like.

For example, an administrator may find it preferable to separate e-maildata from financial data using two different sub-clients havingdifferent storage preferences, retention criteria, or the like. Thesystem 200 may contain not only physical devices, but also may representlogical concepts, organizations, and hierarchies. For example, a firststorage operation cell 200 may be configured to perform a first type ofstorage operations such as HSM operations, which may include backup orother types of data migration, and may include a variety of physicalcomponents including the storage manager 202 (or management agent 210),the media agent 234, the client component 218, and other components asdescribed herein. A second storage operation cell (not shown) maycontain the same or similar physical components, however, it may beconfigured to perform a second type of storage operations such asstorage resource management (SRM) operations, and may include asmonitoring a primary data copy or performing other known SRM operations.

Generally speaking, storage manager 202 may be the same or similar tothe storage managers 140 described with respect to FIGS. 1C-1E, and maybe a software module or other application that coordinates and controlsstorage operations performed by storage system 200. For example, thestorage manager 202 can store and execute the storage policy of thestorage network environment. Storage manager 202 can communicate withsome or all elements of storage system 200 including, but not limited toclients 218, media agents 234, and storage devices 236, to initiate andmanage system backups, migrations, and data recovery. In addition, thestorage manager 202 can include a number of components including, butnot limited, to a jobs agent 204, an interface agent 206, an index 208,and a management agent 210.

The jobs agent 204 can monitor the status of some or all storageoperations previously performed, currently being performed, or scheduledto be performed by storage system 200. The jobs agent 204 can becommunicatively coupled with an interface agent 206 (typically asoftware module or application).

The interface agent 206 can include information processing and displaysoftware, such as a graphical user interface (“GUI”), an applicationprogram interface (“API”), or other interactive interface through whichusers and system processes can retrieve information about the status ofstorage operations. Through interface 208, users may optionally issueinstructions to various storage operation cells 200 regardingperformance of the storage operations as described and contemplated bythe present disclosure. For example, a user may modify a scheduleconcerning the number of pending snapshot copies or other types ofcopies scheduled as needed to suit particular needs or requirements. Asanother example, a user may employ the GUI to view the status of pendingstorage operations in some or all of the storage operation cells in agiven network or to monitor the status of certain components in aparticular storage operation cell (e.g., the amount of storage capacityleft in a particular storage device).

Storage manager 202 maintains an index 208, which can also be referredto as a database, or other data structure. The data stored in thedatabase 208 can be used to indicate logical associations betweencomponents of the system, user preferences, management tasks, mediacontainerization and data storage information or other useful data. Forexample, the storage manager 202 can use data from the database 208 totrack logical associations between the media agent 234 and the storagedevices 236 (or movement of data as containerized from primary tosecondary storage).

In certain embodiments, the storage manager 202 includes a managementagent 210 that is typically implemented as a software module orapplication program. In general, management agent 210 provides aninterface that allows various management components in other storageoperation cells 200 to communicate with one another. For example, acertain network configuration includes multiple cells 200 adjacent toone another or otherwise logically related in a wide area network (WAN)or local area network (LAN) configuration (not shown). With thisarrangement, each cell 200 may be communicatively coupled to the otherthrough each respective interface agent 206. This allows each cell 200to send and receive certain pertinent information from other cells 200including status information, routing information, information regardingcapacity and utilization, or the like.

For example, a management agent 210 in a first storage operation cellmay communicate with a management agent 210 in a second storageoperation cell regarding the status of storage operations in the secondstorage operation cell. Another illustrative example includes the casewhere a management agent 210 in a first storage operation cellcommunicates with a management agent 210 in a second storage operationcell to control the storage manager 202 (and other components) of thesecond storage operation cell via the management agent 210 contained inthe storage manager 202.

Each client 218 can be a separate computing device, a virtual machineinstantiated on a host device, or a host device hosting one or morevirtual machines. Furthermore, each client 218 can include one or moredata agents 212, and one or more data stores 220. The data store 220 canbe a local storage device or can be remotely located and communicatewith the client over a network, such as a LAN, WAN, etc. In someembodiments, the data store 220 can be physical memory residing within aclient computing device. In certain embodiments, such as when the client218 is a virtual machine, the data store 220 can be a storage device(s)or portion thereof. Generally any type of client data can be stored inthe data store 220. For instance, the data store 220 can store files,applications, programs, and other data accessible by the client 218.

Data agent 212 may be the same or similar to the data agents 142described with respect to FIGS. 1C-1E. The data agent 212 may be asoftware module or part of a software module that is generallyresponsible for copying, archiving, migrating, and recovering data fromclient computer 218 stored in an information store 220 or other memorylocation. In some embodiments, one data agent 212 and the system cansupport multiple client computers 218. In certain embodiments, the dataagent 212 can be distributed between the client 218 and the storagemanager 202 (and any other intermediate components) or can be deployedfrom a remote location or its functions approximated by a remote processthat performs some or all of the functions of data agent 212.

Embodiments of the present disclosure may employ multiple data agents212 each of which may backup, migrate, and recover data associated witha different application executing on the respective client computingdevice. For example, different individual data agents 212 may bedesigned to handle Microsoft Exchange data, Lotus Notes data, MicrosoftWindows file system data, Microsoft Active Directory Objects data, andother types of data. Other embodiments may employ one or more genericdata agents 212 that can handle and process multiple data types ratherthan using the specialized data agents 212 described above.

If a client computer 218 has two or more types of data, one data agent212 may be used for each data type to copy, archive, migrate, andrestore the client computer 218 data. For example, to backup, migrate,and restore all of the data on a Microsoft Exchange 2000 server, theclient computer 218 may use one Microsoft Exchange 2000 Mailbox dataagent 212 to backup the Exchange 2000 mailboxes, one Microsoft Exchange2000 Database data agent 212 to backup the Exchange 2000 databases, oneMicrosoft Exchange 2000 Public Folder data agent 212 to backup theExchange 2000 Public Folders, and one Microsoft Windows 2000 File Systemdata agent 212 to backup the client computer's 218 file system. In suchembodiments, these data agents 212 may be treated as four separate dataagents 212 by the system even though they reside on the same clientcomputer 218.

Alternatively, other embodiments may use one or more generic data agents212, each of which may be capable of handling two or more data types.For example, one generic data agent 212 may be used to back up, migrateand restore Microsoft Exchange 2000 Mailbox data and Microsoft Exchange2000 Database data while another generic data agent may handle MicrosoftExchange 2000 Public Folder data and Microsoft Windows 2000 File Systemdata, or the like.

Data agents 212 may be responsible for arranging or packing data to becopied or migrated into a certain format such as an archive file.Nonetheless, it will be understood this represents only one example andany suitable packing or containerization technique or transfermethodology may be used if desired. Such an archive file may include alist of files or data objects copied in metadata, the file and dataobjects themselves. Moreover, any data moved by the data agents 212 maybe tracked within the system by updating indexes associated appropriatestorage managers or media agents.

The system 200 further includes one or more destination storage devices216, which can include storage devices capable of performing snapshotoperations (e.g., hardware and/or software snapshot operations). Thestorage devices 216 can include locally attached storage with snapshotcapabilities. The storage devices 216 can comprise redundant arrays ofindependent disk (RAID) arrays, for example. For instance, thedestination storage devices 216 in some embodiments are configured tocreate and/or store snapshot copies (in addition to non-snapshot copies)of production data that is generated by applications running on theclients 218, such as the production data stored in the data stores 220.For example, the destination storage devices 216 can be capable ofperforming hardware-based snapshots (e.g., storage array-based hardwaresnapshots). The snapshots can be point-in-time images of the productiondata, or of copies of the production data, including replicated copies,for instance. Although a variety of snapshot techniques are compatiblewith the embodiments described herein, in some embodiments, thesnapshots can be created by maintaining pointers to unchanged data andcopying changed data (e.g., blocks), using a copy-on-write methodology,for example.

As shown, the clients 218 can be in communication with the destinationstorage devices 216. In the illustrated embodiment, each of the clients218 is in communication with a corresponding set of one or moredestination storage devices 216. For instance, each set of destinationstorage devices 216 may be local to and/or dedicated the correspondingclient 218. Each client 218, together with its corresponding informationstore 220, may be referred herein as a source storage system. Moreover,each destination storage device 216 or group of destination storagedevices 216 may additionally be associated with a correspondingcomputing device, and the destination storage device(s) 216, togetherwith its corresponding computing device, may be referred to as adestination storage system.

In other embodiments, the clients 218 share access to one or more of thedestination storage devices 216. For instance, multiple clients can haveaccess to one or more same storage devices 216. Such a configuration isdepicted in FIG. 2B, where each of the clients 218 is configured forcommunication with any of the specialized storage devices 216 (e.g.,over a network such as LAN or WAN). In such a configuration, for a givensnapshot operation, the storage manager 202 may direct the correspondingclient 218 to perform the snapshot using a particular selected one ofthe specialized storage devices 216. In other cases, one or more of theclients are in communication with subsets (e.g., overlapping subsets) ofthe destination storage devices 216.

In some cases there is more than one type of destination storage device216, such as where the some of the destination storage devices 216 arefrom different vendors. For instance, a destination storage systems of afirst type and a second type may provide the same general functionality(e.g., disk-based data storage and snapshot capability), the underlyingtechnical implementations of that functionality differ. Referring toFIG. 2A, for example, in one embodiment at least one of the clients 218interfaces with at least two destination storage devices 216 havingdifferent types. In another embodiment, one of the clients 218interfaces with one or more destination storage devices 216 having afirst type, and at least another of the clients 218 interfaces with oneor more destination storage devices 216 having a second type differentthan the first type. FIG. 2B depicts an example where the clients 218are in communication with one or more destination storage devices 216having a first type (TYPE A), one or more destination storage deviceshaving a second type (TYPE B), and one or more destination storagedevices 216 having a third type (TYPE C). Generally any number ofdifferent types of destination storage devices can be present. In oneembodiment, all of the destination storage devices 216 are configured toperform snapshot operations (e.g., hardware snap-shot operations). Forinstance, the storage devices 216 of TYPE A are hardware snapshotdevices from a first vendor and/or having a first underlying technicalimplementation, the storage devices 216 of TYPE B are hardware snapshotdevices from a second vendor having a second underlying technicalimplementation, and the storage devices 216 of TYPE C are hardwaresnapshot devices from a third vendor, having a third underlyingtechnical implementation.

In such cases, the clients 218 can include a common snapshot interface213 (e.g., an API) for communicating with the different types ofdestination storage devices 216. For instance, the client 218 may haveaccess to implementations (e.g., DLL's) of the common snapshot interface213 for each type of destination storage device 216. And, depending onthe particular destination storage device 216 being used for a givendata storage operation, the client 218 will access the correspondingimplementation of the common interface 213 for performing the snapshotoperation. This technique is described further, with respect to FIGS.2-4, for example.

The destination storage device(s) 216 may store replicated versions ofproduction data from corresponding client(s) 218. For instance, in someembodiments, the system 200 includes componentry configured to implementcontinuous data replication (CDR), such that data is copied continuouslyor substantially continuously from the clients 218 to the destinationstorage device(s) 216. Examples of CDR processes and configurationsusable with embodiments described herein are provided in U.S. Pat. No.7,651,593, issued Jan. 26, 2010, U.S. Pat. No. 7,661,028, issued Feb. 9,2010, and U.S. Patent Application Publication No. 2011/0246430,published Oct. 6, 2011, the disclosures of which are hereby incorporatedherein by reference in their entirety. Where replicated copies of datafrom a client system 218 are stored on a destination storage device 216,the destination storage device 216 may create one or more snapshot ofthe replicated copies.

A media agent 105 may be the same or similar to the media agents 144described with respect to FIGS. 1C-1E. Generally speaking, a media agent234, may be implemented as software module that conveys data, asdirected by storage manager 202, between a client computer 218 andsecondary storage including one or more storage devices 236. Thesecondary storage devices 236 can generally include any type of physicalmedia capable of storing electronic data, such as the migrated data fromthe destination storage device(s) 216. In certain embodiments, secondarystorage 236 comprises media configured for long-term data retention,such as tape media or the like. In yet other embodiments, the secondarystorage 236 can comprise a disk or other type of mass storage. Forexample, in certain embodiments, the secondary storage 236advantageously comprises a slower access time and/or a less expensivestorage medium than the destination storage device(s) 216. As a fewexamples, the secondary storage device(s) can include a tape library, amagnetic media storage device, an optical media storage device, or anyother suitable storage device.

As shown in the illustrated embodiment, media agents 234 can be used toconvey data from destination storage devices 216 (e.g., snapshot capabledevices) to the storage devices 236.

In one embodiment, the media agent 234 may be communicatively coupledwith and control a storage device 236. A media agent 234 may beconsidered to be associated with a particular storage device 236 if thatmedia agent 234 is capable of routing and storing data to particularstorage device 236.

In operation, the media agent 234 associated with a particular storagedevice 236 can instruct the storage device to use a robotic arm or otherretrieval means to load or eject a certain storage media, and tosubsequently archive, migrate, or restore data to or from that media.The media agent 234 can communicate with a storage device 236 via asuitable communications path such as a SCSI or fiber channelcommunications link. In some embodiments, the storage device 236 can becommunicatively coupled to a media agent 234 via a storage area network(“SAN”).

Each media agent 234 can maintain an index, database, or other datastructure which stores index data generated during backup, migration,and restore and other storage operations as described herein. Forexample, performing storage operations on Microsoft Exchange data cangenerate index data. Such index data provides a media agent 234 or otherexternal device with a fast and efficient mechanism for locating datastored or backed up. Thus, in some embodiments, the index of the mediaagent 234, or a storage manager database 208, can store data associatinga client 218 with a particular media agent 234 or storage device 236,for example. The data can be stored as specified in a storage policy,while a database or other data structure in media agent 234 may indicatewhere specifically the client 218 data is stored in storage device 236,what specific files were stored, and other information associated withstorage of client 218 data. In some embodiments, such index data may bestored along with the data backed up in a storage device 236, with anadditional copy of the index data written to index cache in a secondarystorage device. Thus, the data is readily available for use in storageoperations and other activities without having to be first retrievedfrom the storage device 236.

Generally speaking, information stored in cache is typically recentinformation that reflects certain particulars about operations that haverecently occurred. After a certain period of time, this information issent to secondary storage and tracked. This information may need to beretrieved and uploaded back into a cache or other memory in a mediaagent before data can be retrieved from storage device 236. In someembodiments, the cached information may include information regardingformat or containerization of archive or other files stored on storagedevice 236.

While not shown, in other embodiments, media agents can be used toconvey data from the clients 218 (e.g., from the data stores 220) to thedestination storage devices 216 and/or directly from the clients 218 tothe secondary storage devices 236. In such cases, the media agents canbe configured to some or all of the functions associated with the mediaagents 234 described with respect to FIGS. 2A-2B. For instance, one ormore media agents can be installed on some or all of the clientcomputing devices 218.

In some embodiments, certain components may reside and execute on thesame computer. For example, in some embodiments, a client computer 218includes the storage manager 202 and coordinates local archiving,migration, and retrieval application functions as further described inU.S. patent application Ser. No. 09/610,738, now issued as U.S. Pat. No.7,035,880. This client computer 218 can function independently ortogether with other similar client computers 218. In another embodiment,a client computer 218 includes a media agent 234.

Moreover, clients 218 and media agents 234 may each have associatedindices and databases. However, in some embodiments each “tier” ofstorage, such as primary storage, secondary storage, tertiary storage,or the like, may have multiple or a centralized database. For example,in FIG. 2A, rather than having a separate database associated with eachclient 218, the databases on this storage tier may be centralized.Similarly, second and other tiers of storage may have either centralizedor distributed databases. Moreover, mixed architectures systems may beused if desired, that may include a first tier centralized databasesystem coupled to with a second tier storage system having distributeddatabases and vice versa.

Moreover, in operation, a storage manager 202 or other management module210 may keep track of certain information that allows the storagemanager 202 to select, designate, or otherwise identify databases to besearched in response to certain queries as further described herein.Movement of data between primary and secondary storage may also involvemovement of associated metadata and other tracking information.

In certain embodiments, the system 200 performs file or block-levelsingle instancing, or de-duplication, of the data stored on thedestination storage devices 216 and/or the data stored in theinformation store(s) 220. Examples of single instancing methods andstructures usable with embodiments of the invention are discussed inU.S. patent application Ser. No. 12/145,342, filed Jun. 24, 2008,published as U.S. Patent Application Publication No. 2009-0319585 A1,which is hereby incorporated herein by reference in its entirety to beconsidered part of this specification. In yet other embodiments, thesystem 200 is configured to perform one or more of the following copyoperations on the data stored in the storage device(s) 216 and/or thedata stored in the information store(s) 220: archiving, backup,Hierarchical Storage Management (“HSM”) copies, Information LifecycleManagement (“ILM”) copies or the like.

As described, certain components in the system 200 may communicate withone another over a network, such as for communications between one ormore of the storage manager 202 and the client(s) 218, the storagemanager 202 and the media agent(s) 234, the client(s) 218 and thedestination storage device(s) 216, the destination storage device(s) 216and the media agent(s) 234. The network(s) can generally comprise anymeans for communicating data between two or more systems or components.It certain embodiments, the network(s) comprises a computer network. Forexample, the network(s) may comprise a public network such as theInternet, a virtual private network (VPN), a token ring or TCP/IP basednetwork, a wide area network (WAN), a local area network (LAN), anintranet network, a point-to-point link, a wireless network, a cellularnetwork, a wireless data transmission system, a two-way cable system, aninteractive kiosk network, a satellite network, a broadband network, abaseband network, combinations of the same or the like. In someembodiments, separately illustrated components are part of the samecomputing device. For instance, one or more of the clients 218 and oneor more of the destination storage devices 216 may be part of the samecomputing device. In such cases, the computers can communicate via acommunications socket or other suitable internal data transfer path ormechanism.

Common Snapshot Interface Overview

FIG. 3A illustrates an example data storage system 300 implementing ageneric snapshot programming interface 328 providing compatibility witha variety of different types of snapshot-capable (e.g., hardwaresnapshot-capable) destination systems 316.

The system 300 includes a storage manager 302, a source system 312, andat least one destination storage system 316. In general, the componentsshown in FIG. 3A may be similar to or the same as correspondingcomponents shown in FIGS. 2A and/or 2B. For instance, one or more of thestorage manager 302, source system 312, data agent(s) 318, sourcestorage 320, and destination system 316 may be similar to or the same asthe storage manager 202, client(s) 218, data agent(s) 218, informationstore(s) 220, and destination storage device(s) 216, respectively, ofFIGS. 2A and/or 2B. Moreover, while not shown in FIG. 3, the destinationsystem 316 may be in communication with one or more media agents, whichmay in turn be in communication with one or more secondary storagedevices in a manner similar to the systems 100 of FIGS. 1A-1B.

The destination system 316 is configured to perform snapshot operations,including hardware snapshots (e.g., storage array-based hardwaresnapshots), for example. And, as discussed with respect to FIGS. 1A-1B,the source system 312 may be configured to operate with multipledifferent types of destination systems 316. For instance, in FIG. 3A,the illustrated destination system 316 may be of a first type (e.g.,corresponding to a particular storage product from a first vendor and/orhaving a first underlying technical implementation), and the sourcesystem may be compatible with at least a second, and preferably more,types of destination system 316 (e.g., corresponding to particularstorage products from second, third, or more vendors and also havingdifferent corresponding technical implementations). As just a fewexamples, the destination system 316 can include snap-shot capablehardware storage arrays or other products available from Hewlett Packard(e.g., 3PAR, EVA and XP), IBM (e.g., SVC, DS, N and XIV), NetApp (e.g.,E-series, FAS [including NFS]), Dell (e.g., Compellent, Equallogic andMD), EMC (e.g., VMAX, CLARiiON, Symmetrix & Celerra) and HDS (e.g., VSP,USP & AMS).

The destination system 316 includes a snapshot engine 317, storage 319,and a shared library 330. The destination storage 319 can include mayinclude any type of physical media capable of storing electronic data.For example, the destination storage 319 may comprise magnetic storage,such as a disk or a tape drive, or other type of mass storage. Incertain embodiments, the destination storage 319 may be internal and/orexternal to (e.g., remote to) one or more other components of thedestination system 316. In yet other embodiments, the destinationstorage 319 can include a NAS or the like. In certain embodiments, thedestination storage 319 includes relatively fast access times ascompared to tape or other relatively slower or less expensive media. Forinstance, the destination storage can include hard disk drives (HDD's)including spinning media or solid state drives (SDD's) includingsolid-state storage, such as flash-based or DRAM-based SSD's.

The shared library 330 (e.g., a DLL) can implement and/or be incompliance with the specification of, the common programming interface328. And the shared library 330 can be accessed by the source system 312when requesting that snapshot operations be performed by the destinationsystem 316. Interaction between the programming interface 328 and thedestination system 316 will be described further below.

The snapshot engine 317 may be a firmware module executing on thecorresponding destination system 316. In some embodiments, the snapshotengine 317 is a software module executing on the storage device, or isimplemented in hardware on the destination storage device 316. Thesnapshot engine 317 is configured to manage requested snapshotoperations, internal to the destination system 316. Where the storagesystem(s) 316 comprises a hardware snapshot devices, the snapshot engine317 for that storage system manages the creation of a snapshot on thecorresponding storage device 319. Depending on the type of thedestination system 316, the implementation of the snapshot engine 317can vary. For instance, the snapshot engine 317 of a destination system316 provided by a first vendor may be different than the snapshot engine317 of a destination system 316 provided by a second vendor or than asnapshot engine 317 of a different type of destination system 316provided by the first vendor.

In embodiments where the destination systems 316 are configured toperform hardware snapshot operations, the snapshot engine 317 may beconfigured to perform the snapshot operation entirely internally to thedestination system 316, without any involvement from external componentssuch as the client computing device 312. For instance, as will bedescribed, the source system 312 may request that a snapshot operationbe performed, and forward the request along with appropriate parametersto the destination system 316. Afterwards, the source system 312 is notinvolved in the performance of the snapshot operation, and simply waitsfor an indication from the destination system 316 regarding the resultsof the snapshot operation. In another embodiment, the snapshot engine317 performs the snapshot operation substantially internally to thedestination system 316, without significant involvement from externalcomponents.

In certain embodiments, the destination system 316 includes one or moreseparate computing devices (not shown). For instance, where replicationis used (e.g., CDR), the destination system 316 may include a separatecomputing device in communication with the destination system 316 andincluding a replication module configured to manage replication of thedata stored in the source storage 320.

The source system 312 includes one or more applications 322, one or moredata agents 318, and a snapshot management layer 324 executing thereon.The applications 322 can include software applications executing on thesource system 312 and generally generate and modify production data. Asjust a few examples, the software applications 322 may include databaseapplications, server software, virtual machine managers, operatingsystems, file system management software, and other types ofapplications.

The source storage 320 can include a data store for storing theproduction data generated by the applications 322. The source storage320 can include may include any type of physical media capable ofstoring electronic data. For example, the source storage 320 maycomprise magnetic storage, such as a disk or a tape drive, or other typeof mass storage. In certain embodiments, the source storage 320 may beinternal and/or external to (e.g., remote to) one or more othercomponents of the source system 312. In yet other embodiments, thesource storage 320 can include a NAS or the like. In certainembodiments, the source storage 320 includes relatively fast accesstimes as compared to tape or other relatively slower or less expensivemedia. For instance, the destination storage can include hard diskdrives (HDD's) including spinning media or solid state drives (SDD's)including solid-state storage, such as flash-based or DRAM-based SSD's.

The data agents 318 may be the same as or similar to the data agents 212described with respect to FIGS. 2A-2B, for example, and may generallymanage the movement of the production data from the applications to thesource storage 320 and/or other locations in the storage system 300. Insome embodiments, the data agents 318 manage movement of the productiondata to the destination system 316 for storage in destination storage319, either directly, or indirectly (e.g., from the source storage 320),depending on the embodiment. The data agents 318 can also be responsiblefor backing up, archiving, migrating or otherwise creating copies ofproduction data on secondary storage (not shown), either directly, orvia one or more media agents (not shown).

Each data agent 318 may be application-specific and associated with acorresponding application 322, such as any of the applications or typesof applications 322 discussed herein. For instance, without limitation,there can be application-specific data agents 318 for DB2, Informix,Microsft Exchange, Microsoft Hyper-V, Microsoft SharePoint Server,Microsoft SQL Server, Oracle, SAP, and for the Microsoft Windows, Linuxand Unix file systems. Alternatively, the data agents 318 may begeneric, where each data agent 318 is capable of handling two or moredata types, generated by different applications 322. The data agents insome embodiments process the data to provide application-consistentstorage of production data.

In some embodiments, the data agents 318 and or media agents (not shown)are in communication with the snapshot management layer 324 and areresponsible for conducting data and metadata between the snapshotmanagement layer 324 and the source storage 320 during snapshotoperations.

The snapshot management layer 324 can be a software module that isgenerally configured to manage interaction with the destination system316 to carry out snapshot operations. The snapshot operations caninclude, without limitation, snapshot creation, snapshot mounting,snapshot unmounting, snapshot deletion and snapshot reversion. Otherpossible operations include operations for obtaining a list of generatedsnapshots, obtaining information related to the amount of storage spaceused by the snapshot(s), obtaining other desired information related tosnapshot(s), setting one or more snapshot attributes, etc. Thecomponents of the snapshot management layer 324 in some embodiments worktogether to gather and/or package the appropriate data and metadatarelated to the requested snapshot operation for transmission to thedestination system 316.

As discussed, the implementation of the components in the destinationsystem 316 can vary. For instance, while any compatible type ofdestination system 316 may be capable of storing production data andprovide snapshot capability (e.g., hardware snapshot capability), theunderlying components of destination systems 316 provide by differentvendors (or for different products provided by the same vendor) isgenerally different. Thus, it is desirable for the source system 312 tobe compatible with a wide array of different types of destinationsystems 316.

The common programming interface 328 (e.g., an API) provides a genericinterface for interfacing with a wide variety of types of destinationsystem 316, so long as the given destination system 316 operates incompliance with the specification of the common programming interface328. For instance, the common programming interface 328 includesspecifications for a set of common functions and/or associated datatypes for each of a plurality of different storage operations (e.g.,different snapshot operations). In certain embodiments, the commonprogramming interface specifies one or more of the following aspects ofeach function (e.g., each snapshot function): (1) input parameters; (2)output parameters; (3) expected functional behavioral; and (4) datatypes for the input parameters and/or output parameters. An exampleprogramming interface 328 including a set of common function definitionsand data definitions is provided below.

While the common programming interface 328 provides a generic interfacefor interacting with the different types of destination systems 316, theimplementation of the underlying functionality defined by theprogramming interface 328 will vary depending on the underlyingarchitecture of the particular destination system 316. Thus, for a givendestination system 316, the snapshot management layer 324 can haveaccess to a separate shared library 330, that can be an executablelibrary 330 (e.g., a DLL or other shared library) implementing thecommon programming interface 328, where the implementation of the sharedlibrary 330 is specific to the type of the given destination system 316.For instance, where each destination storage device 316 is associatedwith a different vendor, each vendor may create and/or provide access toan instance of the library 330. As shown, in some embodiments, theshared library 330 is stored on the destination system 316, and can beaccessed from the destination system 316 by the source system 312.

Before interacting with the particular destination system 316 to carryout a snapshot operation, the snapshot management layer 324 may accessthe instance of the shared library 330 from that destination system 316.The management layer 324 can then invoke the appropriate function callsin the library for performing the snapshot operation on the device 316.In some cases, the management layer 324 accesses the DLL or otherlibrary 330 from some source other than the destination system 316, suchas a server hosted by the particular vendor. In some configurations, themanagement layer 324 accesses the library 330 from an external source(e.g., from the destination system 316) only initially, such as onstart-up of the source system 312 or destination system 316 or prior tothe first time the source system 312 requests a snapshot operation orother operation from the destination system 316. The management layer324 may then register and store the library locally for use insubsequent snapshot or other operations involving that destinationsystem 316. In yet other embodiments, the shared library 330 ispre-installed on or bundled with on the source storage system 312.

The snapshot management layer 324 can be optionally pre-configured forinteracting with certain types of destination systems 316, without usingthe programming interface 328 or shared library 330. For example, thebuilt-in snapshot interface 326 can be a software module or other typeof module including pre-configured functionality for interacting with atleast one type of destination system 316. As such, for destinationstorage systems 316 where the built-in interface 316 providespre-configured support, the snapshot management layer 324 utilizes thebuilt-in interface 326 for interacting with the destination storagedevices 316 instead of by accessing a shared library 330 (e.g., a vendorsupplied DLL) implementing the common snapshot programming interface328.

In certain embodiments, the snapshot management layer 324 or portionsthereof are implemented on a proxy system (not shown) that is separatefrom the source system 312, instead of, or in addition to beingimplemented on the source system 312. The proxy system can therefore beconfigured to perform some or all of the snapshot management processing,thereby alleviating the associated burden from the source system 312 andimproving performance of the source storage system 312.

Example Snapshot Operations

FIG. 3B is an example flow diagram depicting an operational flow for asnapshot operation involving the common programming interface 328. Atsteps 1 a-1 b production data is generated by one or more of the clientapplications 322 and moved to source storage 320, by the data agent(s)318 (e.g., in an application-specific and/or application-consistentmanner). The production data according to some embodiments is sentdirectly to the destination system 316 for storage as primary data inthe destination storage 319 (e.g., a snapshot capable hardware storagearray). In some other cases, the destination system 316 maintains a theprimary data on the source storage 320 or a portion thereof (e.g., oneor more mirrored or replicated copies of production data or portionsthereof [e.g., one or more volumes]). And, where more than onedestination system 316 is used, each of the destination systems 316 maymaintain some or all of the production data (or copies thereof). Forinstance, each destination system 316 can maintain a separate copy ofall of the production data for redundancy. Or, in one embodiment, eachdestination system 316 maintains a different portion of the productiondata, such as one or more particular file system volume(s).

At step 2, a copy of the production data is created on the destinationstorage 319. For instance, the copy may be a replication or backup copy.Or, as previously indicated, in some other cases, the production data isstored directly on destination storage 319, and the destination system316 maintains a primary copy of the production data.

At step 3, the storage manager 302 requests that a snapshot operation beperformed on the production data or a portion thereof. While the storagemanager 302 can request a variety of snapshot operations, for thepurposes of the example, the storage manager 302 issues a snapshotcreation operation requesting that a snapshot be taken of some or all ofthe production data. The request is received by the snapshot managementlayer 324 for processing. Depending on the type of requested snapshotoperation, the request can include a variety of information, includingan identifier indicating the type of requested snapshot operation, asnapshot identifier identifying a previously created snapshot(s) that isthe subject of a request (e.g., a mount, unmount, delete or revertrequest), information identifying which portion of production is thesubject of a requested snapshot (e.g., particular volume(s)). In someembodiments, and for some types of snapshot operations, the managementlayer 324 requests a copy of any appropriate production data from sourcestorage 320 for use in the snapshot operation.

The snapshot management layer 324 processes the request received fromthe storage manager 302. For instance, the snapshot management layer 324can determine or otherwise obtain the type of the target destinationsystem 316. The determination can be made by sending an inquiry over aSmall Computer System Interface (SCSI) or other appropriate bus, e.g.,to the destination system 316, or to some other device maintaining suchinformation, such as a device that maintains a logical volume manager(LVM). In some embodiments, the management layer 324 determines whetheror not the built-in snapshot interface 326 includes built-in support forthat particular target destination system 316. In the example shown inFIG. 3B, the destination system is of a first type (TYPE A), and is notsupported by the built-in snapshot interface 326. Thus, the managementlayer 324 attempts to interact with the destination system 316 via thecommon programming interface 328.

For example, at step 4, the snapshot management layer 324 accesses theshared library 330 associated with the particular destination system 316and/or associated with the type of the destination system 316, where thelibrary 330 complies with the specifications of the common programminginterface 328. In some embodiments, the source system 312 includes apre-installed copy of the library 330 (e.g., stored in the sourcestorage 320) and accesses the pre-installed copy instead of accessingthe library 330 from the destination system. For instance, the library330 is instantiated on the source system 312 during installation (e.g.,installation of the destination system 316) and is loaded into thesnapshot management layer 324 using operating system functions (e.g.,LoadLibrary for Microsoft Windows and DIIOpen for Unix systems).

In some embodiments, where multiple destination systems 316 are used,the management layer 324 may determine which of the destinationsystems(s) 316 are involved in the current snapshot operation. As just afew examples, each destination system 316 may be associated with one ormore file system volumes or directories, with data generated by aparticular application, with a particular type of data, etc. And thestorage manager 302 may include sufficient information in the requestfor the snapshot management layer 324 to determine which destinationstorage system(s) 316 will be used to perform the snapshot operation.For instance, in one embodiment, multiple destination systems 316 may beassociated with different file system volumes, and the snapshot requestinvolves a first volume(s). In the request, the storage manager 302includes an indication of that the first volume(s) is involved in thesnapshot operation, or otherwise includes information sufficient for themanagement layer 324 to derive that the first volume(s) is involved inthe operation. Based on this information, the management layer 324determines that the particular destination system(s) 316 that isassociated with the first volume(s) is to be used to perform thesnapshot operation. In other embodiments, the storage manager 302directly indicates to the snapshot management layer 324 which of aplurality of destination system 316 is to be used to perform thesnapshot operation.

At step 5, the management layer 324 invokes the appropriate functions inthe shared library 330 to initiate performance of the storage request.For instance the management layer 324 processes the snapshot requestfrom the storage manager 302 to determine one or more of the appropriatefunctions to call in the shared library 330, an order in which to callthe functions, and/or a set of appropriate values to provide as inputsto the respective functions. The management layer 324 then causes thesnapshot engine to perform the determined functions. For instance, themanagement layer 324 may transmit to the snapshot engine 317 anindication of the selected functions, the corresponding input values,and/or the specified order of operation. At step 6, the snapshot engine317 executes the specified functions according to the informationreceived from the source system to perform the requested snapshotoperation (e.g., create, mount, unmount, delete or revert a snapshot) onthe destination storage 319. A mount snapshot operation may also bereferred to as a “map” command, and generally causes a snapshot tobecome visible or open to access within the storage fabric network by agiven source system 312. An unmount snapshot operation, on the otherhand, causes the snapshot to become invisible and/or inaccessible to asource system 312. Example mount (“cvso_mapSnaps”) and unmount(“cvso_unmapSnaps”) functions are shown in the example interfaceprovided below. Example snapshot creation (“cvso_snapDevices”), snapshotdeletion (“cvso_deleteSnaps”), and snapshot reversion(“cvso_revertSnaps”) functions are also provided below in the exemplaryinterface. Some other possible snapshot interface functions includeoperations for: identifying the version of the DLL or other sharedlibrary 330 (e.g., “cvso_version”, provided below), preparing adestination storage device 319 for a snapshot operation (e.g.,“cvso_prepareDevices”, provided below), reversing actions that weretaken during an operation that prepared the destination storage device319 for a snapshot operation (e.g., “cvso_unprepareDevices”, providedbelow), and verifying that a snapshot is available for access (e.g.,“cvso_reconcileSnaps”).

At step 7, once the snapshot operation completes, the destination system316 reports the results or status to the management layer 324, e.g., viathe programming interface 328. For instance, the destination system 316returns an indication of whether or not the snapshot operation wassuccessful. As in the example, where the operation is a snapshotrequest, the destination system 316 may return one or more of a snapshotidentifier, a time that the snapshot was created, an array identifier(e.g., serial number of storage array), a group identifier (e.g., groupin which the snapshot resides), and a device status (e.g.,synchronization status of the snapshot, such as for clones).

In some embodiments, more than one destination system 316 can be used toperform the particular snapshot operation. Or, in some embodiments,multiple different snapshot operations occur in parallel on multipledestination systems 316. In yet another embodiment, mirrored snapshotsare maintained on different destination storage devices 316 forredundancy.

FIG. 3C illustrates another example snapshot operation. The exampleshown in FIG. 3C differs from the example shown in FIG. 3B in that thesnapshot operation depicted in FIG. 3C involves a destination systemhaving a type that is supported by the built-in interface 326 of thesnapshot management layer 324. Thus, in contrast to FIG. 3B, themanagement layer 324 determines, e.g., from data embedded in thesnapshot request received from the storage manager 302, that therequested snapshot operation is to be performed on a destination systemhaving a second type (TYPE B) different than the type described abovewith respect to FIG. 3B.

The management layer 324 then determines that the second type (TYPE B)is supported by the built-in snapshot interface 326. Thus, instead ofutilizing the common programming interface as in FIG. 3B, the managementlayer 324 invokes the built-in snapshot interface 326 to interact withsnapshot engine 317 at step 4 to request performance of the snapshotoperation. For example, the management layer 324 may invoke and/orexecute one or more custom functions associated with the destinationsystem 316. In some embodiments, the functions invoked by the built-ininterface do not conform to the specifications defined by the commonprogramming interface 328. Rather, the built-in functions may include orutilize definitions, coding and/or data types specific to the particulartype (TYPE B) of the destination system 316 and not genericallyapplicable to other types of destination systems 316, unlike the commonprogramming interface 328. The remaining steps may be similar to thosedescribed with respect to FIG. 3B. For instance, at step 5, the snapshotengine 317 performs the snapshot on the destination storage 319. At step6, the snapshot engine 317 returns an indication as to the results ofthe operation to the snapshot management layer 324.

FIG. 4 is a flowchart illustrating an example method 400 of performing asnapshot operation. While described with respect to FIGS. 3A-3C, themethod 400 is compatible with any of the data storage systems describedherein, including the data storage systems 200 shown in FIGS. 2A-2B. Atoperational block 402, the data storage system provides a genericprogramming interface. For instance, the generic programming interfacespecification may be communicated to a set of vendors or other partiestasked with implementing the shared library 330. The programminginterface can be an application programming interface (API) that iscodified into an interface definition using a programming language(e.g., C++), and API documentation can be provided therewith. Atoperational block 404, the snapshot management layer 324 receives asnapshot operation request from, e.g., from the storage manager 302. Atoperational block 406, the management layer 324 determines the devicetype associated with the destination system 316 on which the snapshotoperation is to be performed. For instance, the management layer 324 mayextract or derive the identity of the destination system 316 based oninformation included in the snapshot operation request. And, based onthe identity of the destination system 316, the management layer 324 candetermine the type of the subject destination system 316.

At decision block 408, based on the determined type, the managementlayer 324 determines if the built-in snapshot interface 326 includespre-configured, built-in support for interacting with that typedestination system 316. If not, at operational block 410 the managementlayer 324 accesses a library 330 at block 410 that implements the commonprogramming interface 328 for that type of destination storage system316. For instance, the library 330 may include vendor-coded functionscomplying with the specifications set forth by the common programminginterface 328. At operational block 412, the destination system 300performs the snapshot operation. For instance, the management layer 324invokes the appropriate functions in the accessed library 330, causingthe destination storage system 316 to perform the operation, in a mannersimilar to that described with respect to FIG. 3B. The management layer324 loads the library 330 and makes direct calls into the library 330with input parameters provided to the management layer 324. The library330 then communicates with the destination system 316 to carry out theoperation.

On the other hand, if the management layer 324 determines that there isbuilt-in support for the type of the destination system 316, themanagement layer accesses that built-in functionality at block 414 tocause the destination system 316 to perform the snapshot at block 416,e.g., in a manner similar to that described with respect to FIG. 3C.

Example Common Snapshot Interface

A non-limiting example of a generic programming interface will now beprovided. The example programming interface is an API implemented in theC programming language, and may be compiled using a C++ compiler. Theinterface can be implemented by different vendors providing storagedevices capable of performing hardware snapshot operations.

Example Common Snapshot Interface—Example Functions

The following are example functions provided by the example genericsnapshot programming interface:

/** * return library version. This information is used for referenceand * will be logged into the log file. * * @param major major version *@param minor minor version * @param revision revision version */ voidCVSO_API cvso_version(  int16_t* major,  int16_t* minor,  int16_t*revision);cvso_version return library version. This information is used toidentify DLL version. This information will be logged into the log file(CVMA.log).

/** * Verify's if character device charDeviceName belongs to the arraythat * this library supports. SNAP_TYPE filed will indicate what kind ofsnap * is to be performed. Library can return error message when erroroccurred and * errBuf is not NULL. The size of the errBuf is limited byerrBufSize−1. * This method can be used to automatically discover theengine. * * @param charDeviceName character device name * @param typesnap type expected (SNAP_TYPE::CLONE, SNAP_TYPE::SNAP, * SNAP_TYPE::ANY) * @param errBuf buffer to return error message forlogging * @param errBufSize size of the buffer * @returnCVSO::RC_SUCCESS indicates that charDeviceName is supported. * CVSO::RC_FAIL_PARTIAL is not supported and CVSO:: RC_FAIL value * indicate an error. */ CVSO::ResultCode CVSO API cvso_isSupported( const char* charDeviceName,  CVSO::SNAP_TYPE type,  CVSO::CVOSUtil*osutil,  char* errBuf,  int16_t errBufSize );cvso_isSupported should verify if character device charDeviceNamebelongs to the array that this library supports. SNAP_TYPE filed willindicate what kind of snap is involved (SNAP or CLONE). Library canreturn error message when error occurred and errBuf is not NULL. Thesize of the errBuf is limited by errBufSize-1. This will be used toautomatically discover the engine type.

/** * Called to prepare device provided in array for hardware snap. * Itshould perform operation on array for upcoming snap operation. * Updateinformation in the each item from the array for next * operation orcancelation. * This function should expect physical device path(character device) and * snap type provided for each item in thearray. * The status for each item in the array should be setREADY_FOR_SNAP_or * READY_FOR_SNAP_FAILED in case of failure. * @paramarray array of the CVSO::SnapInfo classes * @param count number of itemsin the array * @return CVSO::RC_SUCCESS when all items status is set toREADY_FOR_SNAP, * CVSO::RC_FAIL_PARTIAL when one or more items status isset to * READY_FOR_SNAP_FAILED, CVSO::RC_FAIL when all items status isset * to READY_FOR_SNAP_FAILED */ CVSO::ResultCode CVSO_APIcvso_prepareDevices(  CVSO::SnapInfo ** array,  int16_t count, CVSO::CVOSUtil* osutil );cvso_prepareDevices called to prepare device provided in array forhardware snap. It should perform appropriate operations on the array foran upcoming snap operation and/or update information in the each itemfrom the array for next operation or cancelation. This function shouldexpect physical device path (character device) and snap type providedfor each item in the array. The status for each item in the array shouldbe set READY_FOR_SNAP or READY_FOR_SNAP_FAILED in case of failure.

/** * Undo any operations that was done during cvso_prepareDevice incase * when snap operation is canceled or prepare failed for some of theitems. * The status for each item in the array should be set CANCELED orCANCEL_FAILED. * @param array array of the CVSO::SnapInfo classes *@param count number of items in the array * @return CVSO::RC_SUCCESSwhen all items status is set to CANCELED, * CVSO::RC_FAIL_PARTIAL whenone or more items status is set to CANCEL_FAILED, * CVSO::RC_FAIL whenall items status is set to CANCEL_FAILED */ CVSO::ResultCode CVSO_APIcvso_unprepareDevices(  CVSO::SnapInfo ** array,  int16_t count, CVSO::CVOSUtil* osutil );cvso_unprepareDevices called when snap operation is canceled or preparefailed for some of the items. The status for each item in the arrayshould be set CANCELED or CANCEL_FAILED.

/** * Perform actual snap operation for all items in the array and setstatus * to SNAPED or SNAP_FAILED as well as other fields. * @paramarray array of the CVSO::SnapInfo classes * @param count number of itemsin the array * @return CVSO::RC_SUCCESS when all items status is set toSNAPED, * CVSO::RC_FAIL_PARTIAL when one or more items status is set toSNAP_FAILED, * CVSO::RC_FAIL when all items status is set to SNAP_FAILED*/ CVSO::ResultCode CVSO_API cvso_snapDevices(  CVSO::SnapInfo ** array, int16_t count,  CVSO::CVOSUtil* osutil );cvso_snapDevices perform actual snap operation for all items in thearray and set status to SNAPED or SNAP_FAILED as well as all othernecessary fields.

/** * Map snaps provided in the array and map to the client machine. *This call is similar to cvso_isMapped except it will map, locate OS *device when it is not mapped. * The character device name should be setusing setSnapDevice. * @param array array of the CVSO::SnapInfoclasses * @param count number of items in the array * @returnCVSO::RC_SUCCESS when all items status is set to AVAILABLE, *CVSO::RC_FAIL_PARTIAL when one or more items status is not set to *AVAILABLE, CVSO::RC_FAIL when all items status is not set to AVAILABLE.*/ CVSO::ResultCode CVSO_API cvso_mapSnaps(  CVSO::SnapInfo ** array, int16_t count,  CVSO::CVOSUtil* osutil );cvso_mapSnaps map snaps provided in the array to the client machine. Thecharacter device name should be set using setSnapDevice.

/** * Unmap snap from the host. * This call should not remove OS devicesfrom the host. * The status for each item in the array should be set toUNMAPPED when * snap is unmapped from the host. * Status UNMAPP_FAILEDshould be set when unmap failed. * Status should be set to UNKNOWN whensnap not found on the hardware array. * @param array array of theCVSO::SnapInfo classes * @param count number of items in the array *@return CVSO::RC_SUCCESS when all items status is set to UNMAPPED, *CVSO::RC_FAIL_PARTIAL when one or more items status is set toUNMAPP_FAILED, * CVSO::RC_FAIL when all items status is set toUNMAPP_FAILED. */ CVSO::ResultCode CVSO_API cvso_unmapSnaps( CVSO::SnapInfo ** array,  int16_t count,  CVSO::CVOSUtil* osutil );cvso_unmapSnaps nnmap snap from the host. This call should not remove OSdevices from the host. The status for each item in the array should beset to UNMAPPED when snap is unmapped from the host. StatusUNMAPP_FAILED should be set when unmap failed. Status should be set toUNKNOWN when snap not found on the hardware array.

/** * Delete snaps provided in the array and set status to DELETED. *This function is called when snap failed or we don't need snapanymore. * Status should be set to UNKNOWN when snap not found on thehardware array. * Status should be set to DELETE_FAILED in case offailure. * @param array array of the CVSO::SnapInfo classes * @paramcount number of items in the array * @return CVSO::RC_SUCCESS when allitems status is set to DELETED, * CVSO::RC_FAIL_PARTIAL when one or moreitems status is not set to DELETED, * CVSO::RC_FAIL when all itemsstatus is not set to DELETED. */ CVSO::ResultCode CVSO_APIcvso_deleteSnaps(  CVSO::SnapInfo ** array,  int16_t count, CVSO::CVOSUtil*osutil );cvso_deleteSnaps delete snaps provided in the array and set status toDELETED. This function is called when snap operation failed or we don'tneed snap anymore.Status should be set to UNKNOWN when snap not found on the hardwarearray. Status should be set to DELETE_FAILED in case of failure.

 /**  * Perform hardware revert for each item in the array.  * Statusshould be set to REVERTED in case of success.  * Status should be set toREVERT_FAILED when revert failed.  * Status should be set to UNKNOWNwhen snap not found on the  hardware array.  * @param array array of theCVSO::SnapInfo classes  * @param count number of items in the array  *@return CVSO::RC_SUCCESS when all items status is set to  CANCELED,  *CVSO::RC_FAIL_PARTIAL when one or more items status is set to CANCEL_FAILED,  * CVSO::RC_FAIL when all items status is set toCANCEL_FAILED  */  CVSO::ResultCode CVSO_API cvso_revertSnaps(CVSO::SnapInfo  ** array, int16_t count, CVSO::CVOSUtil* osutil );cvso_revertSnaps perform hardware revert for each item in the array.Status should be set to REVERTED in case of success. Status should beset to REVERT_FAILED when revert failed. Status should be set to UNKNOWNwhen snap not found on the hardware array.

 /**  * Verify if Snaps provided in array are available on the filer.  *Status should be set for each Snap as EXT_DELETE when snap is  notavailable.  * If operation can't be completed or snap is available thestatus should  * not be changed.  * @param array array of theCVSO::SnapInfo classes  * @param count number of items in the array  *@return CVSO::RC_SUCCESS when all items are available on  the filer,CVSO::RC_FAIL_PARTIAL  * when one or more item's status set withEXT_DELETE, or CVSO::  RC_FAIL when  * operation can't be completed.  */ CVSO::ResultCode CVSO_API cvso_reconcileSnaps( CVSO::  SnapInfo **array, int16_t count, CVSO::CVOSUtil* osutil );cvso_reconcileSnaps verifies if Snaps provided in array are available onthe filer. Status should be set for each Snap as EXT_DELETE when snap isnot available. If operation can't be completed or snap is available thestatus should not be changed.

Example Common Snapshot Interface—Example Data Definitions

The following are example data definitions provided by the examplegeneric snapshot programming interface:

Class SnapInfo

The SnapInfo class represents a snap or clone that is associated with aLUN. The interface of this class allows DLL code to set or get propertyof the snap. The Snap has following standard properties:

Snap UUID: unique identifier of the snap that is known by array. TheUUID can be assigned to the snap or clone based on a value from thisproperty and do not change it. In some cases, when array does not allowchanging or setting custom snap or clone name, the DLL should set snapUUID based on assigned to clone or snap identifier by array.

/** * Get Sanp Unique Identifier * By default this value is provided asCV_{CommCell ID}_ {Snap ID} * @param buf will be populated with SnapUnique Identifier * @param bufSize size ofthe buffer. * @returnCVSO::RC_SUCCESS, CVSO::RC_FAIL_PARTIAL - buf is too small *  andbufSize will be set with size of the data. */ virtual ResultCodegetSnapUUID( char* buf, int16_t& bufSize) = 0; /** * Set Snap UniqueIdentifier * @param uuid snap Unique Identifier * @returnCVSO::RC_SUCCESS, CVSO::RC_FAIL */ virtual ResultCode setSnapUUID( char*uuid ) = 0;

Array Information: Each array can be registered in SnapBackup database.The registration information includes:

- hostid - reference number in the database table - engineId  /**  * GetArray info.  * Array info returned in jason format(http://www.json.org/)  * Fields:  *  hostid  *  engineId  *  portNumber *  hostFlags  *  hostStatus  *  hostOption  *  sourceId  *  vendorName *  arrayId  *  hostIp  *  hostName  *  hostUserName  *  hostPassword  * engineName  *  deviceGroupName  *  reserve1  *  reserve2  *  reserve3 * @param arrayinfo buffer to return jason formated array information  *@param infoSize size of the arrayinfo buffer  * @returnCVSO::RC_SUCCESS, CVSO::RC_FAIL - error,  *   CVSO::RC_FAIL_PARTIAL -buf is too small and bufSize will be set  *   with size of the data.  */ virtual ResultCode getArrayInfo( char* arrayinfo, int16_t& infoSize ) =0;  /**  * Provides array name to map Array Info to the Snap  * @paramhostName array host name  * @return CVSO::RC_SUCCESS, CVSO::RC_FAIL -error,  *   CVSO::RC_FAIL_PARTIAL - array not found in database.  */ virtual ResultCode setArrayInfo( const char* hostName) = 0;  /**  *Associate Array Info using array control host name  * @param hostNamearray host name  * @return CVSO::RC_SUCCESS, CVSO::RC_FAIL - error,  *CVSO::RC_FAIL_PARTIAL - array not found in database.  */  virtualResultCode setArrayInfoByCtrlHostName ( const char* controlHostName ) =0;  /**  * Get host identifier to use while call CVOSUtil methods  *@param buf buffer to store host identifier (will be provided  *   informat //hostname or empty)  * @param bufSize size of the buffer  *@return  */  virtual ResultCode getHostIdentifier( char* buf, int16_t&bufSize ) = 0;  /**  * Get Snap Type  * @return in case of error −1 willbe returned, otherwise snap  *   type id is returned  */  virtualint16_t getSnapType( ) = 0;  /**  * Set snap type  * @param snapTypesnap type id  * @return CVSO::RC_SUCCESS, CVSO::RC_FAIL,  *  CVSO::RC_FAIL_PARTIAL - the value is not allowed  */  virtualResultCode setSnapType( int16_t snapType ) = 0;  /**  * Check if flagspassed as flagMask are set  * @param flagMask bit mask for the flags  *@return true if all flags from flagMask is set, false if one or  *   allflags are not set  */  virtual bool isFlagSet( int32_t flagMask) = 0; /**  * Add flag(s) spicified in flagMask to the snap flag  * @paramflagMask bit mask for the flags  * @return CVSO::RC_SUCCESS,CVSO::RC_FAIL - error,  *   CVSO::RC_FAIL_PARTIAL - some of the flagsare not allowed  *   to be changed by Engine Layer  */  virtualResultCode setFlag( int32_t flagMask) = 0;  /**  * Returns the flag set.This is needed just to get the whole flagMask  * when one needs to passit across.  */  virtual int32_t getFlag () = 0;  /**  * Remove flag(s)spicified in flagMask to the snap flag  * @param flagMask bit mask forthe flags  * @return CVSO::RC_SUCCESS, CVSO::RC_FAIL - error,  *  CVSO::RC_FAIL_PARTIAL - some of the flags are not allowed  *   to bechanged by Engine Layer  */  virtual ResultCode clearFlag( int32_tflagMask) = 0;  /**  * Get current snap status  * @return snap status */  virtual SnapStatus getStatus( ) = 0;  /**  * Set new snap status  *@param status new status  * @return CVSO::RC_SUCCESS, CVSO::RC_FAIL -error  */  virtual ResultCode setStatus( SnapStatus status ) = 0;  /** * Get OS local device name (character device) for source device where * sanp will be taken or was taken  * @param buf buffer to store devicename  * @param bufSize size of the buffer  * @return CVSO::RC_SUCCESS,CVSO::RC_FAIL - error,  *   CVSO::RC_FAIL_PARTIAL - buf is too small andbufSize will  *   be set with size of the data.  */  virtual ResultCodegetSourceDevice( char* buf, int16_t& bufSize) = 0;  /**  * Set OS localdevice name where Source is mapped to the host,  * should be called onlyin case of revert if needed  * @param buf device name  * @returnCVSO::RC_SUCCESS, CVSO::RC_FAIL - error  */  virtual CVSO::ResultCodesetSourceDevice ( const char* buf) = 0;  /**  * Get OS local device name(character device) known to be a Snap  * mapped to the host  * @parambuf device name  * @param bufSize size of the buffer  * @returnCVSO::RC_SUCCESS, CVSO::RC_FAIL - error  */  virtual ResultCodegetSnapDevice( char* buf, int16_t& bufSize) = 0;  /**  * Set OS localdevice name (character device) where Snap is  * mapped to the host  *@param buf device name  * @return CVSO::RC_SUCCESS, CVSO::RC_FAIL -error  */  virtual ResultCode setSnapDevice( const char* buf) =0;  /** * Get Shadow Copy Id (Windows only)  * @param buf buffer to storedevice name  * @param bufSize size of the buffer  * @return uniqueidentifier  */  virtual ResultCode getShadowCopyId( char* buf, int16_t&bufSize) = 0;  /**  * Set Shadow Copy Id (Windows only)  * @param bufdevice name  * @return CVSO::RC_SUCCESS, CVSO::RC_FAIL - error  */ virtual ResultCode setShadowCopyId( const char* buf) = 0;  /**  * Getmeta data associated with snap  * @param typeId meta data type  * @parambuffer c-string for meta data  * @param bufSize size of the meta databuffer (maximum data will be  *   stared in buffer is bufSize−1).  *@return CVSO::RC_SUCCESS, CVSO::RC_FAIL - error,  *  CVSO::RC_FAIL_PARTIAL - buf is too small and bufSize will  *   be setwith size of the data.  */  virtual ResultCode getMetaData( int16_ttypeId, char* buffer, int16_t& bufSize) = 0;  /**  * Set/delete metadata associated with snap.  * Meta data of the same type will bereplaced.  * Meta data of type typeId will be deleted if c-string lengthis 0 or  * it is passed as NULL.  * @param typeId meta data type  *@param buffer c-string data  * @return CVSO::RC_SUCCESS, CVSO::RC_FAIL -error,  *   CVSO::RC_FAIL_PARTIAL - data is too large  */  virtualResultCode setMetaData( int16_t typeId, char* buffer) = 0;  /**  * Logerror code and message  * @param errorCode error code, 0 - no error, anyother value - error  * @param msg error messages  */  virtual voidsetError( int32_t errorCode, const char* msg ) = 0;  /**  * Gets theerrorCode and the Message  * @param errorCode error code, 0 - no error,any other value - error  * @param msg error messages  */  virtual voidgetError( int32_t &errorCode, char* msg) = 0;  /*  * Log message in msgto the CommVault current log file with log  * level set to LogLevel  *@param level log level  * @param msg c-string message  */  virtual voidlogMessage( LogLevel level, const char* msg ) = 0;  /**  * Log messagein msg to the CommVault current log file with log  * level set toLogLevel  * @param Debug Lvl log level  * @param function c-string withfunction name that is send the messages  * @param msg c-string formatstring for message  */  virtual void logMessage(int DebugLvl, const char*function, const char *umessage, ...)  = 0;  /**  * Set the GroupId bit.This will group luns lying on the same  * array volume (especially forNetApp) in one group  * This information can then be used by the engineto create one  * snap / group instead of one snap per lun.  * @paramint16_t iGroupId groupid  */  virtual CVSO::ResultCode setGroupId(intiGroupId) = 0;  /**  * Get the GroupId bit.  * @return int16_tiGroupId - groupid  */  virtual int getGroupId( ) = 0;

Terminology

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements and/or steps areincluded or are to be performed in any particular embodiment.

Depending on the embodiment, certain acts, events, or functions of anyof the algorithms described herein can be performed in a differentsequence, can be added, merged, or left out all together (e.g., not alldescribed acts or events are necessary for the practice of thealgorithms). Moreover, in certain embodiments, acts or events can beperformed concurrently, e.g., through multi-threaded processing,interrupt processing, or multiple processors or processor cores or onother parallel architectures, rather than sequentially.

Systems and modules described herein may comprise software, firmware,hardware, or any combination(s) of software, firmware, or hardwaresuitable for the purposes described herein. Software and other modulesmay reside on servers, workstations, personal computers, computerizedtablets, PDAs, and other devices suitable for the purposes describedherein. Software and other modules may be accessible via local memory,via a network, via a browser, or via other means suitable for thepurposes described herein. Data structures described herein may comprisecomputer files, variables, programming arrays, programming structures,or any electronic information storage schemes or methods, or anycombinations thereof, suitable for the purposes described herein. Userinterface elements described herein may comprise elements from graphicaluser interfaces, command line interfaces, and other suitable interfaces.

Further, the processing of the various components of the illustratedsystems can be distributed across multiple machines, networks, and othercomputing resources. In addition, two or more components of a system canbe combined into fewer components. Various components of the illustratedsystems can be implemented in one or more virtual machines, rather thanin dedicated computer hardware systems. Likewise, the data repositoriesshown can represent physical and/or logical data storage, including, forexample, storage area networks or other distributed storage systems.Moreover, in some embodiments the connections between the componentsshown represent possible paths of data flow, rather than actualconnections between hardware. While some examples of possibleconnections are shown, any of the subset of the components shown cancommunicate with any other subset of components in variousimplementations.

Embodiments are also described above with reference to flow chartillustrations and/or block diagrams of methods, apparatus (systems) andcomputer program products. Each block of the flow chart illustrationsand/or block diagrams, and combinations of blocks in the flow chartillustrations and/or block diagrams, may be implemented by computerprogram instructions. Such instructions may be provided to a processorof a general purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the acts specified in the flow chart and/or block diagramblock or blocks.

These computer program instructions may also be stored in acomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to operate in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement the acts specified in the flow chart and/or blockdiagram block or blocks. The computer program instructions may also beloaded onto a computer or other programmable data processing apparatusto cause a series of operations to be performed on the computer or otherprogrammable apparatus to produce a computer implemented process suchthat the instructions which execute on the computer or otherprogrammable apparatus provide steps for implementing the acts specifiedin the flow chart and/or block diagram block or blocks.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel methods and systems describedherein may be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the describedmethods and systems may be made without departing from the spirit of thedisclosure. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the disclosure.

1.-21. (canceled)
 22. A data storage system, comprising: a source systemin communication with a destination system comprising a first storagedevice, the first storage device configured to perform snapshotoperations; and one or more processors configured to: receive a requestto perform a snapshot operation of at least a portion of data stored onthe first storage device; determine that the source system does notinclude pre-configured functionality for causing the first storagedevice to perform the snapshot operation; communicate with thedestination system to identify one or more functions for performing therequested snapshot operation that are compatible with a programminginterface residing on the source system; and invoke an instance of theone or more identified functions using the programming interface,wherein a snapshot engine residing on the destination system performsthe requested snapshot operation in response to invocation of theinstance of the one or more identified functions.
 23. The data storagesystem of claim 22, wherein the instance of the one or more identifiedfunctions is accessed from a shared library associated with the firststorage device.
 24. The data storage system of claim 23, wherein theshared library is located at the destination system and is accessed bythe source system.
 25. The data storage system of claim 22, wherein thefirst storage device is configured to perform hardware snapshots. 26.The data storage system of claim 22, wherein the requested snapshotoperation includes one or more of a snapshot creation operation, asnapshot mount operation, and a snapshot revert operation.
 27. The datastorage system of claim 22, wherein the source system comprises the oneor more processors.
 28. The data storage system of claim 22, wherein thesource system is in communication with a second storage device of asecond type that is configured to perform snapshot operations, andwherein the one or more processors are further configured to: receive arequest to perform a second snapshot operation of at least a portion ofdata stored on the second storage device; determine that the secondstorage device is a different type of storage device from the firststorage device; determine that the source system includes one or morepre-configured functions for causing the second storage device toperform the second snapshot operation; and instruct a snapshot engineresiding on the second storage device to perform the requested secondsnapshot operation based at least in part on the one or morepre-configured functions.
 29. The data storage system of claim 28,wherein the one or more identified functions are provided by a firstvendor and the one or more pre-configured functions provided by a secondvendor.
 30. The data storage system of claim 22, wherein the one or moreprocessors are further configured to cause storage devices of anothertype to perform snapshot operations without using the programminginterface.
 31. The data storage system of claim 30, wherein thepre-configured functionality includes one or more functions that are notcompatible with the programming interface.
 32. The data storage systemof claim 22, wherein the source system comprises the one or moreprocessors.
 33. The data storage system of claim 22, wherein a proxycomputing device that is separate from the source system comprises theone or more processors.
 34. A method of performing one or more snapshotoperations on data generated in a data storage system, the methodcomprising: receiving a request to perform a snapshot operationinvolving a portion of data stored on a first storage device of adestination system, the first storage device configured to performsnapshot operations; determining that the source system does not includepre-configured functionality for causing the first storage device toperform the snapshot operation; communicating with the destinationsystem to identify one or more functions for performing the requestedsnapshot operation that are compatible with a programming interfaceresiding on the source system; and invoking, using one or more computerprocessors, an instance of the one or more identified functions usingthe programming interface, wherein the destination system is responsiveto the invoking of the instances of the one or more identified functionsto perform the requested snapshot operation.
 35. The method of claim 34,further comprising accessing the instance of the one or more identifiedfunctions from a shared library associated with the first storagedevice.
 36. The method of claim 35, wherein the shared library islocated at the destination system and is accessed by the source system.37. The method of claim 34, wherein the first storage device isconfigured to perform hardware snapshots.
 38. The method of claim 34,wherein the requested snapshot operation includes one or more of asnapshot creation operation, a snapshot mount operation, and a snapshotrevert operation.
 39. The method of claim 34, wherein the source systemis in communication with a second storage device of a second type andthat is configured to perform snapshot operations, the method furthercomprising: receiving a request to perform a second snapshot operationinvolving at least a portion of the data that resides on the secondstorage device; determining that the second storage device is a secondtype of storage device different from the first type of storage device;determining that the source system includes one or more pre-configuredfunctions for causing the second storage device to perform the secondsnapshot operation; and instructing a snapshot engine residing on thesecond storage device to perform the requested second snapshot operationbased at least in part on the one or more pre-configured functions. 40.The method of claim 39, wherein the one or more identified functions areprovided by a first vendor and the one or more pre-configured functionsprovided by a second vendor.
 41. The method of claim 34, wherein thesource system includes pre-configured functionality for causing storagedevices of another type to perform snapshot operations without using theprogramming interface.